small and medium poket pair

[jerseys]

Hi, I play 0.10/0.20 and sometimes 0.15/0.30 on Party Poker. The problem I have is with playing small and medium poket pairs.

I know how to play AA-JJ. But one of my biggest concerns is TT-77. TT especially. Starting game chart in SSHE says you can even raise with it. But for me it VERY rarely wins UI. Smaller PP I most often tend to fold. From what I understand, you need a lot of players in the pot before entering with a small PP from late and especially tight players that can make a top pair at the flop. But to me there never seems to be enough players in the pot to even return my investment in small PP. I never even play small and medium PP from the MP.

So, I need some general pointers. How to recognise right circumstances for playing a small or medium PP? How many players need to be in the pot? What kind of players they should preferably be? Should I b/f on the flop if an overpair comes or c/f?