I have been going BF shopping for years by myself and prefer it that way! I can go where I want, when I want and stay as long as I want.
Like others mentioned, there are always people to chat with in line nearby and you learn their strategies as well.
I circle all the items I am interested in seeing the day before with a large black marker and try to put them in order of the stops I’ll make. I leave them in the car and take only the ad with me for that store (unless I’m price matching).
I bring fruit and bottled water in the car to eat/drink between stops. I don’t bring a chair since I can’t really return to my vehicle. I try to dress in layers so that if I am overheated, I can wear fewer layers at the next stop. I don’t like carrying a big bulky coat so depending on the length of time in the line, I might not take it. I live in north Florida, so it’s not terribly cold. The rain is usually the problem, so I have a collapsible umbrella and will just put it in my purse.
I do take out all unnecessary credit cards, frequent shopper cards, and other purse stuff so that I am not too overloaded and can carry my purchases adequately.