There may be no easy solution to your problem. Even native speakers have problems when they choose words from the huge English vocabulary. The only guidelines that I can suggest are: (l) Read as much as you can (including the comic strips), (2) Converse as much as possible with native speakers, (3) Watch a lot of English-language television and movies, (4) Listen carefully to song lyrics, (5) Consult the best dictionaries and thesauruses, and (6) In general, choose the shorter rather than longer word.
New words, one handy idiom, and a 2-minute quiz — delivered to your inbox to keep your streak alive.