If you have already got AC in any question, then there is no need to retry the same problem. Codeforces has a lot of problems to try. But if you didn't get AC then do try the same problem. Read the editorial if you don't get the solution and you must implement the solution (unless you don't understand the solution).

Try problems that are slightly harder than your comfort level (You can look at Code-Drills for recommended problems)

Other than solving problems, virtual contests are a good way of practicing cp. I recommend participating in 2-4 contests every week.

I sometimes revise old problems where I wrote a long and cumbersome code, or if I forgot how to solve the problem — so I can see if I solve it faster this time.