I play multitable slightly passive 50NL.

with mid-pairs (66-99?) I generally limp in EP and raise in MP/LP if it's folded to me, and call small raises when the stacks are deep enough. Sometimes I'll put a lot of pressure on small stacks with 77-99. 99 I always raise with regardless of pos.

Open-limping is not that great, but I'll do it sometimes as the tables are relatively tame.

When people reraise my raises and I have a mid pp, I look at the size of their raise, the size of their stack (and mine, obviously, but I'm usually around the max buy-in), and how aggressive I'm being perceived before I call. So many people min-reraise that I get really good odds to hit a set.