Separable verbl?

how can you tell a word is a separable verb in german i’ve been trying to figure this out do you just to memorise them as you go along

You’ll have to memorize quite a few but there are a couple of rules that help:
a) Among the particles that can be bothf the particle is stressed in forms that are no separated (such as the infinitive) then it’s separable. If it’s not stressed, then it’s not separable:
'übergehen: separable; über’winden: not separable
b) Most of the particles are either always separable or always not separable, zum Beispiel:

I remember this is one of the things that I worried about back in the day.

The truth is, in my opinion, is that we just learn these things by “brute force”. That is to say: when you have seen or heard a particular verb hundreds of times, you’ll tend to “feel” whether it’s separable or not…

My advice is to learn by heart a few model examples of grammar, so that the “theory” is clear in your mind. But the wider practical application can only happen through mass exposure, most probably.

Buckel up and enjoy the ride!