losing $0.10, a few questions

My stats are 19/10, running -10BB/100 over 2,400 hands at the $0.10 tables. I was playing SNGs before this and considered myself a decent player, but after a long SNG losing streak I moved to cash and I've obviously got some major leaks or just a complete lack of skill altogether. So here are some random questions -

When I raise limpers preflop, am I trying to bet just enough to fold them out or just little enough to keep them in? I find that some limpers will regularly call 6bb raises in any position, and I'm unsure whether to raise higher next time.

I see a lot of TAGGs that only buy in half of the max or even less. What do you make of these? Is there any valid reason to do this, or are they probably unskilled postflop and just have the saving grace of a decent starting range? I'm the only player at most tables who auto max rebuys.

About half the players seem to be LPASS preflop. But postflop I have a really hard time figuring them out. When they call down hands on every street, they may well have air or the nuts. They will sometimes bluff on the river. Beating them sounds straightforward - don't bluff, but bet heavy (75-150% of pot, or raise higher if villain bets) with a strong middle pair or better or when semi bluffing with strong draws, double or triple barreling, and commit to see the river most of the time unless things look horribly bad. But in doing this strategy I lose more in folding so many hands preflop or postflop and in bad beat showdowns than I win in showdowns or pricing them out. I feel as though I've gotten better at value betting, but the better I get, the more I lose somehow. Is there another major component to beating these type of players? Are there sharks who play so LPASS preflop, stats such as 35/10, or am I almost certainly psyching myself out?