Be able to discuss the big-O complexity of your approaches. Don't forget to brush up on your data structures like lists, arrays, hash tables, hash maps,
stacks, queues, graphs, trees, heaps. Also sorts, searches, and traversals(BFS, DFS). Also review recursion and iterative approaches.
Use the programming language you're best at. It's important to write your solution correctly and in time, so use the language you are most familiar with.
Find and fix the bugs by yourself: Don't wait for the interviewer to find them for you.
Use the hints you are given: Usually, the interviewer knows the question well enough to know which hints will help you next if you get stuck.