What topics should I study as a beginner to get better in CP?

I have been doing competitive programming for the last 3 months, I have given around 12 contests on codeforces and a few on codechef .On codeforces, I am barely able to solve A question, till date I have solved around 104 question on Cf but still not improving pls suggest what topic should I study as a beginner to get better in CP.

Well, CF problems A and B are mostly ad-hoc type. U can like study number theory and solve related problems. Mostly till date what I have observed is in a div 3 contest of CF , A problem will be of either string manipulation , pattern searching or something related to array permutation. CF A-B problems mostly revolve around like there are two numbers find their max GCD or find any number in between which satisfy some condition etc or find peak elements in array with some condition etc.
I suggest what you do is select 1000-1100 rating and do only number theory, greedy, constructive algorithms, implementation problems.