what to do on one excursion from cruiseship into glasgow

A great way to spend a single day in Glasgow is to buy a one day hop on, hop off bus ticket. These go every 10 minutes, and alternate between taped commentary and live commentary. They go to almost all the top attractions in town.

Get on a live commentary bus and stay on for one full ride. Then, get on and off at any attractions that appeal to you. Many of the attractions are free. The Tenement Museum does have an admission charge, but it was one of my favorites.

As for what to see, look at Rick's Scotland or Great Britain book. He has an excellent chapter on Glasgow (same chapter in both books).

When my sister and I visited Glasgow four years ago, we used the hop-on-hop-off for only part of a trip around and wished later we had done what Harold suggests: ride the full way one time and then visit a museum.

We both enjoyed the free transportation museum and the boat behind, https://www.glasgowlife.org.uk/museums/venues/riverside-museum

We also used the Glasgow subway to return to the hotel, http://www.spt.co.uk/subway/ and that was one of my favorite trip experiences. My impression was that it wasn't big or flashy, but it was fast and furious! A complete circuit is only 24 minutes, so not much time of your day to include it :-)

You can check toursbylocals.com and put in Glasgow. They have a link for shore excursions. You can read what each guide offers and decide. They pick you up and return you right to the pier. We used them in Edinburgh and went to Sterling with a stop in Calendar for lunch and at Doone Castle.

If you are interested in Charles Rennie McIntosh, you could have tea at the Willow Tea Room.

I forgot to add, if you want to see what I did with four days in Glasgow, here's my trip report; just skip the Liverpool and Manchester sections (unless, of course, your ship goes to Liverpool too): https://community.ricksteves.com/travel-forum/trip-reports/uk-trip-report-glasgow-manchester-liverpool-in-september-2016

https://www.tomsportguides.com/uploads/5/8/5/4/58547429/greenock_scotland-08-28-2012.pdf

There's a helpful guide, I've just recently discovered the Tom's Port site and I really like it. RS does a great job with ports but so does this Tom guy and he takes quite a different approach than RS.

Please be aware that it is about one hour from Greenock to central Glasgow.

The "true" Willow Tea Room in Sauchiehall Street is currently still closed for restoration. The one in Buchanan Street is a modern revival.

I would visit the Riverside Museum--it was formerly the transportation museum. My second spot would be to visit the Tenement Museum. There is a sister museum here in NYC. Both museums are wonderful and give you perspective on what it was like to live in a tenement.