[kadoban]

Practicing is _very_ helpful. pramp.com is good for getting over the nerves and practicing the (approximate) format. For the actual problems, there's a lot of resources out there. Cracking the Coding Interview is not a bad place to start. If you really want to get good, do competitive programming. Read Laaksonen's Competitive Programming book, practice on cses.fi/problemset , codeforces.com , hackerrank.com , codechef.com , etc. If you have the time, study CLRS Introduction to Algorithms.

(not affiliated with any, just resources I enjoyed and found useful)

[zer0sand0nes]

Any reason you didn't mention Leetcode? I'm all over leet code right now.

[kadoban]

I personally just hate leetcode for largely subjective reasons. Its problems tend to be poorly specified and uninteresting compared to the other places, editorials are spotty, and there's too much push to pay for a subscription for my tastes.

If you're into it though, I wouldn't push you to abandon it, whatever keeps you going is best (and I know at least one person I know has improved a lot there)