First Time to Venice

2.5 days is not a long time for a first trip, although I guess that's how long I stayed the first time (3 nights). My primary interest in visiting Venice was photography and site seeing - I had no interest in museums or going inside certain buildings. (I was alone and had zero interest in a gondola ride.) What are you interested in? Leaf through the Rick Steves Italy book Venice section and see what might interest you.

I think a vaporetto (water bus) ride up the Grand Canal is probably the one essential thing I'd suggest. You'll do lots of walking anyway, but try to get off the main drags and walk in less busy areas, because the busiest areas like Riato and San Marco get mobbed with people and it can be very unpleasant. I quite enjoy the walk between Rialto and Santa Lucia train station - but on the south side of the canal, not along the straight, busy Strada Nova. Mornings and evenings are best for walking before the mobs of tour groups arrive or wake up in the mornings.

You know, there's this guy named Rick Steves who covers this pretty extensively in books and videos ...

A few of the things I enjoyed:

• Take a vaporetto from the train station to St. Mark's square. Rick Steves has an audio tour along this route that is a great introduction to the city

• St. Mark's square has the basilica, which is a must see. Book online at least a day in advance to reserve a time slot

• Also at St Mark's, I really enjoyed the Doge's Palace and the "Secret Itineraries" tour that shows you the dungeons, interrogation chamber, etc.

• Walking between St. Mark's and the Rialto Bridge, and then visiting the Rialto market is a good way to see some of the central sites. Rick has an audio tour for this as well. It gets quite busy through mid-day, so better to do in the morning or evening

• Separate from the glassblowing tour, which I agree is skippable, taking a vaporetto out to Murano and/or Burano islands makes nice boat ride and you can check out a few shops to see what the glass is all about. An even shorter boat ride stops at the cemetery island, which is worth a short stop

• There are dozens of churches if you are interested in art/churches. The Frari basilica was my favourite (and also is covered by an audio tour)

Spend the first day following the crowd so you don’t miss the top sights. Also tour St. Mark’s Basilica and buy tickets before leaving home so you don’t have to wait in that long line. At twilight take a vaporetto ride from one end of the canal to the opposite end i.e., St. Mark’s Square and the train station. This way you won’t see the decay on the palace exteriors, instead your eye will voyeur inside so you can peak at the grand foyers adorned with humongous crystal chandeliers and spiral staircases. Each palace is unique, the experience took me back in time as my mental walls floated away.

The next day get lost and when you’re ready to get back on the beaten path find the crowd.

As far as meals don’t go inside places with pictures of food outside the entrance. The food is warmed up in a microwave and there’s a lot of them; instead follow your nose and eyes. Venice has more tourists than residents so this isn’t the best place to eat because a repeat clientele is not the norm. I liked the tuna sandwiches that adorned the windows in the cafes.

I’ve been to Venice twice now, the first time as part of the RS Venice/Florence/Rome tour. I arrived a day early for that so I had three days instead of just two. If you read the itinerary for Venice for that tour it will give you a good idea of what you can accomplish with the time you have. Some of us went into the Doges Palace on our free time and I enjoyed that enough that I went back when I was there in May for a week.
Personally, I think one of the must dos is to get out to Burano and Murano, and even a quick stop at Torcello (if you get an early start and head to Burano first, then make your way back, stopping at Torcello then Murano, you should be able to see all three and be back to Venice early afternoon).Burano is known for lace making, and is a very colourful place, great for photos, especially if you get there before the shops start to open and the crowds arrive. Murano is known for glass making, and has a more industrial look because of that, but it is so much fun to wander through all the shops and admire the artistry of the glass makers, and maybe even see some in action.
St. Marks square is pretty much ground zero for the major sight of the Basilica, the tower, the Corer museum, Doges Palace, and you can buy vaporetto tickets there (not all vaporetto stops sell tickets). The major galleries are the Acedemia (mostly religious themes) and the Peggy Guggenheim (modern art). The Rialto bridge area is great for shopping, or just standing on the bridge and watching Venice go by. There are many other museums, and churches with amazing art and architecture, and I would suggest looking at a map of where they are all located and try to find accommodation based on what you want to see. One thing about Venice is that there is not really a straight path to get anywhere, and you will get lost, but that’s half the fun. With limited time you will have to try to be as efficient as you can. Do take a round trip vaporetto ride on the grand canal, day and evening, and a gondola ride at least once. If you want to go up a tower for an aerial view of the city go to San Giorgio, it’s the one you can see across from St. Marks and is cheaper, and doesn’t usually have a line up. It’s o ly one vaporetto stop across from St Marks. I got a city pass that covered entrance to many churches and a few museums and I plotted my daily walking path using the map of sights that came with it. There is a place right on St. Marks, near the Corer museum entrance where you can buy various passes.

The Doges Palace Secret Itineraries tour is very good-
https://palazzoducale.visitmuve.it/en/pianifica-la-tua-visita/special-itineraries/secret-itineraries-tour/

Torcello is the farthest of the three islands (Torcello, Burano, Murano) from the core of Venice. It does take a good bit of vaporetto time to hit all three. I've never tried to do that in one day, but Burano + Torcello was easily manageable. Note that they do not allow photographs inside Santa Maria Assunta on Torcello.

On our first trip we got soooo much help from Rick Steves’ Venice guidebook. You can perhaps find it in the library if you don’t want to purchase it, but it answers so many questions you might not even know to ask. Great info on logistics iof this unique city and great self-guided tours.

Venice is mobbed by tourists. It has been a destination for tourists for about 500 years at least, Shakespeare wrote The Merchant of Venice around 1595, setting it there because the city was well known.
So you won’t escape the crowds, but with a bit of planning you can minimise it.
Ignore the hotel breakfast and get out and about really early, 6:00 AM is good.
Get the book Secret Venice by Jonglez. Full of quirky details, things that are way off the tourist trail. Your teenagers could explore with that book, it would draw them all over Venice.
The Doges Palace takes about 2 1/2 hours, so consider whether it is worth it. Ditto the Basilica.

You could, of course, just ignore all the big ticket things and go kayaking. It’s a total blast.
Venicekayak.com finds them.
I wrote about our journey here:
https://www.fodors.com/community/europe/venice-canoeing-kayaking-975809/

We loved every moment in Venice but the one that stands out most in our minds is our last morning. We got up very early and took the vaporetto to the end and back. We were the only "tourists" on the boat and saw Venice without the crowds which can be a bit overwhelming. We saw the sunrise from the boat which was magnificent. We felt like a local.

We did a guided tour of Doges Palace including the prison and a walk across the Bridge of Sighs. Our guide was fascinating and very well versed in the subject matter. It might be interesting for your teens.

Try not to be overwhelmed. Part of the fun of a trip is the planning phase. Enjoy your trip to Italy!

Rather than take a glass-blowing tour from Venice, just get tickets for the vaparetto and go visit any of the island (Murano, Burano and Torcello) that you have time for. My husband is a glassblower and really was impressed with the glass museum on Murano. If you see a particular item in more than one shop, it’s not produced locally. Wandering up and down the main street gives you glimpses into some beautiful shops.

Chichetti bars are a fun way to have a meal and there are lists on this website if you check the search option. We did eat one meal at 1000 Gourmet Venezia which had all kinds of pizza and needed a reservation for dinner. It’s casual and was very popular.

I would not ask for must do because there is no must. I would check out as many photos as possible and decide what you and your family like most. There must have been a reason to pick Venice and there must have been something attracting your attention.

For me it is all about strolling the streets and absorbing the city vibes. Standing up early and enjoying the beauty of the city without the crowds. Going back to the Hotel having a nice breakfast and back on the street avoiding places where everybody is going to during the day. Later having some nice meal and going back to the famous sights when it's dark and celebrate the fact that they are almost empty. I did this 2 weeks ago and it was a dream. But maybe you and your family are totally different :-)

As mentioned places to eat are all ok as long as you stay away from the tourist traps - pictures on the menue and/or a guy outside the restaurant asking you to come in.

just get tickets for the vaparetto

If you want to visit both Murano AND Burano (I would skip Murano and spend more time in Burano, but that is just me) it would make sense to buy a day pass for the vaporatto.

I was in Venice in 2017 so this may be old news but worth checking out. We arrived in St. Mark’s Square at 8 AM and with the exception of the workers we were the only ones there. We were the first ones into the Doge’s Palace and saw very few people in the time we were there. When we came out there were mobs of tourists. As an aside we found that no matter where we were in Italy getting moving early worked like a charm. in Rome Piazza Navona was empty at 8 AM. Delightful!!

Maybe you already read this, but if not, I recommend you do: https://www.ricksteves.com/watch-read-listen/read/articles and this https://europeforvisitors.com/venice/