Welcome to FTR!!!

22-66 limp after a 2+ limpers, play for set value. If other players are capable of folding post-flop then I raise with one limper if I'm in LP.

77-99 I'll raise with 1-2 limpers, call for set value with 3+. If raising doesn't get people to fold, then be less likely to raise, or try raising more.

Rule of thumb is 3bb + 1bb/limper (if you aren't getting folds try 3bb + 2bb/limper)

When calling raises the rule of thumb is 20x (implied odds). You want the raises to have 20x the amount of the bet left in his stack (and you too). It can be less if he raises and gets 4 callers.

This requires better post-flop play (i.e. you'll end up in trickier situations). But that will make you a better player.