I think the most important quality for a language learner to acquire is independence. At The Linguist www.thelinguist.com I stress this with our tutors. You have to search out your own content of interest. You must become observant of the language. Notice words and phrases that you want to use. When you have trouble saying something, remember what it was. Write it down. Watch for that word or structure when you read or listen. Ask for help when you are with native speakers.
Listen to the pronunciation. Try to practice saying it right. Do not just wait for the teacher to correct you, or to explain the grammar or to tell you how to place your tongue to pronounce correctly. Whatever you find on your own will stay with you. Whatever is just given to you is easily forgotten.
Do not just do your homework. Take the initiative.