Good tip as well: Sometimes files used by plugins aren't considered "used" by the engine, in which case, you can't select "exclude files" during deployment. In that event, you may need to clean out some rtp assets to make the file not unbearable large. Good rule of thumb:
1. Don't delete the vehicles
2. Double check the sideview images aren't used.
3. I, personally, don't touch SEs, BGMS, and animation assets, it's usually just used in mysterious places and a word of caution.
4. Usually tilesets, characters, pictures, and battlebacks are safe to delete. Also usually bgs unless you're using them/have a weather affect plugin.
Good luck and remember to do all final testing on a deployed project! Weird things pop up there that don't on the in engine testor.