getting acclimated

We always take a nap and then hit the streets. I research the neighborhood before leaving home by going to Google Maps and entering the address. Then I hit the "+" a couple of times to magnify the map. Up pops all the neighborhood businesses, etc. in icons. You can also see where the metro and bus stops are on the map.
I always know the neighborhood and names of the streets before I even leave the U.S.

Good suggestions David! I forgot to mention that we would need this in Barcelona and Madrid!

Same as David, except I skip the nap. I even use the street view of Google maps so I know what places look like before arriving. Unless you’re staying in some really small town, you should have no trouble finding a store with everything you need.

I'm useless on my arrival day so don't attempt anything beyond walking around. Whatever feel up for, do leave excess cash, cards, etc., locked up in your hotel room, because you may not exactly be in great shape for avoiding pickpockets on Day 1.

I don't know of anything as specific as you're looking for, but walking tours often include comments about the local situation that will be helpful, as well as useful background/historical information. The "free" tours (you should tip generously) are often a bit more casual and may be the most useful for your purposes; suggestions about good neighborhoods for things like tapas may come up. I have often asked easy-to-answer questions of the guide as the group was walking to the next stop.

Rick's guide books are extremely good about providing orientation information on such subjects as how to use the local transportation system. I highly recommend his guide to Spain. There is very little you might need to know that is not in that book.

There's a very handy, large Carrefour supermarket on La Rambla about two blocks SE of Placa de Catalunya in Barcelona. The market is on two floors. It looks crazy-busy late in the afternoon, but I found the lines moved very fast. About two blocks farther down the same street is La Boqueria. It's now quite touristy but still a handy place to get nibbles if you're hungry at a time that doesn't align with local custom. There's an extremely wide variety of tapas on offer from the various stands.

If you tell us where you are staying in each city, there may be folks on the board who can give you tips.

Are you in apartments? If so, some hosts will shop for you. They will certainly help with grocery stores and needs near buy. Ask beforehand and have uour maps already pinned before arrival.
I always have overnight flights and will take melatonin to get 4-5 hours sleep on the plane, so I can function for enough hours on the ground to get settled in and a short trek to feel oriented. Otherwise a nap, and then groceries. Carrefours are wonderful, but some of the Express neighbourhood shops have short hours Sunday. I found Madrid had alternative mom&pop shops for a starter shop.

Thanks everyone for the great suggestions. We will definitely take your advice on going slow..tours..google maps for help.

The service you want is the Tourist Information center. Stop in a TI your first day to check on any festivals or special events you might not have known about and get a basic walking map to orient yourself.

For me the first day is about getting out, getting a walk in fresh air and forcing myself to use public transportation. I find, after one ride on the metro or bus, it's easy but also easy to let myself procrastinate and not learn it - so first day.

Thanks again everyone great ideas and suggestions!