The second, and I mean the SECOND you leave your guard down in this chess.com jungle or try an opening you are not familiar with, you will be crushed. Even at the sub 200 level where I am, it's like whoops...fumbled the opening and CHECKMATE.
None of the chess theory or other high minded opening b.s. seems to work on here. no one cares that you're playing the Schmendel-Kitzbaum Opening...you will be annihilated at the first opportunity.
All that's worked for me is to abide by some basic opening principles but essentially just play a hard, tight, defensive game early on until something opens up. And (when black) always, always beware the Roving White Queen. Because the second you are not ready for it, some one will bust it out.