I guess a good start is to talk to your self in Korean, and try to think in Korean, as much as possible. Just try to feel as familiar and "at home" with the language as possible.
For example, instead of thinking/saying (to yourself) "hmm, what's this?", you can say/think "이게 뭐지?".
Remember it's totally fine to make mistakes, since the only way to improve is through making mistakes and then learning from them.