Practice. Use pramp.com. Do super super simple ones. If you can't do two sum or fizzbuzz or tree traversals with someone watching you, you're not going to have a prayer for harder stuff. Just start SUPER simple. Pracitce a lot.
It should be muscle memory to do the easy stuff. And then it turns out, the 'hard' questions are often just a combination of easy things.
It should be muscle memory to do the easy stuff. And then it turns out, the 'hard' questions are often just a combination of easy things.