AkamaiBrah
I wouldn't say you failed by any means. A Q of 50 means that you are obviously bright and logical. A V of 16 is "explanable" by someone who is not english-speaking. You have the tools -- do you have the time?
I don't know where you are at as far as you English goes, in addition to whatever you do I suggest reading American newspapers like the NY times or WSJ everyday, or the Economist if you can get it. Reading passages of well written prose everyday will give your "ear" a sense of the proper language.
Good luck.
I completely agree with AkamaiBrah. You are by no means a 'failure.' Scoring a 50 on the quant shows that you are very capable of scoring well on the GMAT.
The problem area for you is in verbal. Next time around, you should focus in on the verbal section. You should not ignore the math section, but you should focus more of your energy on the verbal.
I agree with AkamaiBrah's advice about reading high-level english material, but I think that doing that will be more of a help with reading comp rather than the other sections (grammar and CR). You should read up on english grammar (like PR's *Grammar Smart*) and look through this website for advice on CR.