Mid PP (77-99) were only slight winners for me until I started raising with them from any position when first in, raising out of the blinds, raising from LP with limpers ahead of me and re-raising 2-3X bets ahead of me when on the C/O or button. Generally just being a lot more aggressive with them. Your pair is typically the best hand pre-flop and if you raise enough to isolate a single person you're still good on the flop 2/3 of the time against overs. Even if overs come, your strong pre-flop action allows you to represent hands that can induce better hands to fold.

My problem was that I was playing these hands too much for set value alone. They're strong enough though to play them much more aggressively than I was. I was calling too many 3-6x BB bets looking to set and snap of AA or KK. Well most 3-6xBB raises aren't AA or KK. I was calling off too many bets when I didn't hit my set and wasn't getting paid often enough when I did to make my passive play profitable. I now tend to treat mid-PP like they're the best hand PF, and most of the time they are. Even if they aren't, an aggressive approach allows you to at least make it more convincing that they are.