you must master openings you play and know strategy behind them. For example, when I play queens pawn opening I have elo performance of 2700 where as if i were to play E4 opening I would have an elo of 1500.
How did you arrive at those numbers? And how is it possible that your rating is between 1500 and 2700 (depending on the opening, and according to you), when your rating here on Chess.com is less than 1500? If your statement were true, shouldn't your Chess.com rating be somewhere in between those two numbers? Or do you mostly play games with other openings, openings in which your rating is even lower?
Complete Book of Chess Strategy also by Mr. Silman