I have built my bankroll from $50 to $600 in three months playing the NL 10 and NL 25 Party Poker cash games. However, I have had trouble beating the NL 50 games (have tried at Party and on Everest Poker so far) as players are very aggressive with their made hands (raises, re-raises, check-raises both on the flop and the river), rarely bluff (making you fold a lot in order to save bets) and do not pay me often enough with my made hands for me to make a profit consistently. Right now I find myself with three options:

-Bonus whoring at the NL 25 games at other rooms keeping gambling to a minimum. Playing 6-tables to accelerate the clearing. Clearing bonuses at a level I cannot beat is a losing strategy from my experience.
-Staying at a beatable NL 25 at a room with Rakeback
-Make it to $1500 with the two options above and do online rounding to scout and test NL 50, NL 100 and NL 200 games to find the beatable ones and become a regular there with Rakeback.

Can someone that have moved up from NL 50 at Party Poker tell how to consistently beat those players? Your help is kindly appreciated.