It has happened several times to me that I can't solve a problem in the contest but right after it finishes I come up with the solution.

I'm not worried about being unable to solve all the problems in Div.2 contest, not even some Div.3's, I'm aware I'm simply not good enough (yet?). But not being able to solve in-contest some problems that you can solve with a little more time hits differently.

It's another skill issue, just the fact that it takes me too much time to solve the other problems I manage during the contest.

Any advice on how to stop this from happening?