I have practiced around 300 questions till now and several 1300 and 1400 rated questions also but my rating is not crossing 1300. Is there something I am doing wrong that I can correct in my practice to increase my rating. Or maybe some new technique Practices questions.

Also is there some technique on how to give a contest bcs I tend to solve the 1400 rated questions during practice but unable to solve them during the contest.

Any suggestions are welcome.