Find good and reliable resources and study materials that are just a bit more difficult than your current level.
Stop correcting yourself and criticizing how you sound. Please. If you never say “My English is very bad” or “I only speak a little English” again, then it’s a good start!
Practice regularly and stick with it. Decide how often you want to study. Figure out how to motivate and reward yourself. If you have the means, I recommend scheduling a trip to a place where you are sure to speak English.
Listen, Read, Write, Talk, and Think… all in English!
Find other students, anglophone pen pals, or keep in contact with English-Speaking Friends
*Challenge yourself! If you have a solid habit but never push yourself to the next level, you will not progress.