It's the little words that are hard:

PREPOSITIONS

Take all the small words that follow another word:

eg: Following stop:

stop over (or stopover); stop in; stop off; stop out (or a stopout); stop by;

To STOP OVER

I will stop over with you on the way to Cambridge, if that is all right.

Or: I'm making a stopover at Paris.

STOP OFF

I'll stop off with these things on the way home.

STOP IN

Don't stop in this evening. Come out with us.

STOP OUT

Why did you stop out all night?

but to someone who regularly stops out you might say: "You're a dirty stopout". (Not a nice thing to say but perhaps he deserves it).

STOP BY

Stop by this afternoon and I'll make you a cup of tea. (ie - call round and see me).

Perhaps trying a few of these each day will reinforce your learning. Hope it helps.