I've played 15k hands of 5NL to get a confidence boost before jumping back into the deep waters of lowstakes.
Most of those observations are true for all stakes, but they are especially useful at micros.
5NL on stars is infested with a shitton of nutpeddling regs. So you want to avoid two things: becoming one of them and having too many of them on your tables.
To do that:
Don't join wait lists... ever. Table stats are decieving and mostly useless. Fish don't join waitlists, they get on a table and stick with it until bust. As a result a table will get worse and worse the longer it has been running. Re-evaluate your table selection; close tables and join new ones when they go bad.
Don't open too many tables. If you start timing out on stars extremely generous timebank, it means you have a bunch too many open already.
If you feel somewhat comfortable with shorthanded play: sit on empty tables. They won't stay shorthanded for too long anyway. Don't sit to the directly to the left of other regs who open tables. Besides being bad etiquette it's also not preferrable. You'd rather have a weak fish there than someone who will steal your blinds.
Bet sizing tells:
Just in general most players will bet small with mediocre made hands and draws, and bet big with the top of their range. - be careful with pinning down small bets as weak, but you can safely assume that pot bets are strong.
Min-donkbets: are mostly air and 2nd/3rd pair hands. You can raise your entire range, or get fancy with your value stuff if you desire. you often need to barrel or raise another turn donk - you'll get enough folds to make that profitable.
Timing: Quick betting decisions are mostly strong, especially if they are quick over several streets. Obnoxious time-downs before a raise are always the nuts.
Playing against nits: out-nit them. Don't get involved. Sometimes KK is a fold pre or a setmininig hand at best. Not much value in playing back at a 5/4 without the nuts, ever.
Just general stuff:
Take regular breaks. Try to get poker off your mind while on a break. It's easy to get tunnel vision if you keep your mind on one thing for too long.
Maintain blood flow to the head: If you start feeling fuzzy, get up and do some exercise. Don't be ashamed to give up valuable hands and just sit out on all tables immediately. For me jumping jacks work best.
Don't force thing. Wait to get lucky. Be nice. Don't judge.