First, wearing properly. If you are still transitioning, do not wear clothes that are too feminine. Try to wear some unisex clothes first.
Second, learn how to do makeup. You may still look like a male, but you still have to learn how to do makeup, because one day, you are a woman, you will do makeup.
Third, keep long hair. This is very important for all trans women. Long hair represents femininity. You need that.