Separable prefixes are ruining my life—how do you internalize them?

I'm currently preparing for my first real conversation with a native speaker, and I'm stressing out about separable verbs. Every time I think I have a handle on 'ankommen' or 'aussehen,' I end up putting the prefix in the wrong spot or forgetting it entirely at the end of the sentence. Is there a specific way to practice these without sounding like a broken robot? I am asking specifically about learning German, not a generic study routine.