Now this might sound a bit off coming from me who is also not that well versed but as far "If I'm being punished too much i don't know what to do anymore and just turtle" is concerned: I'd say there are three things (Or rather two major things) you need to study to avoid that, that is the
universal mechanics of KoF (Guard cancels, rolls, safe jumps and other jumps etc.),
character specific mechanics like how good is my character's light punch, can my character dodge a mid air projectile by sweeping, can my down+C stuff a jump in etc. / and at the same time, the characters you know you have problems against. You can be crafty and visit their Sub-Forums here and "Spy" on their tipp's and tricks ;D . (Check out
for some more in XIII)
And lastly, but not less important,
Player habits. Mostly if they have any noticable ones you can take advantage of it after maybe the first few rounds if you haven't already played them before. I casually play with a friend from Korea and his Robert, Ralf and King and Heidern drive me nuts. I know exactly what he is going to do but i rarely find the chance to take advantage of it, say for instance with his King against my Kim, i am definately forced to play a lot safer because Kim doesn't have a lot of meterless anti-projectile options. I am forced to risk and go in after i have seen or "think" i can predict his fireball pattern, and jump in. Now the first few times i do this he usually catches me with trap shot or he mixes a double venom shot in. A few games later and i get the jist of short hopping one projectile until i can get "in reach" (not too close, but not too far) and try and wait something unsafe from him. Then there's another King player i play and he plays her way more aggressively. (I prefer this because close range is my forte) Some things vary from player to player (variable) and some things are set in stone via frame data from your and your opponents character and the game mechanics itself.
This is just my opinion.