Sleeping well helps you to really integrate things you have learned throughout the day, whether that is a mathematical formula or a new grammatical structure. Getting a good nights rest also helps you to feel less stressed and be in a better state of mind when you are learning.
Repetition helps you to remember things you have learned. In addition, repeating words or phrases out loud helps you to work on the muscle memory necessary to say things in the target language.
3. Learn the rhythm
Languages all have a musicality or a distinct rhythm. To improve your accent and to have fewer miscommunications, focus some of your energy on learning the rhythm of the language.
4. Choose short and long term S.M.A.R.T. goals
Specific - know what you want to learn specifically, narrow it down from "I want to be fluent" to "I want to be able to talk about my likes and dislikes." "I want to be able to talk about cooking." "I want to be able to..."
Measurable - Make sure you can measure your success. Maybe make a recording of your first conversation with your tutor, then make another recording after 5 or 10 hours of class and compare. If you want to improve your vocabulary, keep a personal "dictionary" of words you have learned.
Attainable - Make sure the goal is something realistic. You need about 100-200 hours to move from one level of fluency to the next, keep this in mind when thinking about your goals.
Relevant - How are these goals relevant to your life? Will you use what you learn professionally? Are you going to travel? Do you like reading classic literature in the target language?
Time-bound - Give yourself a set amount of time to accomplish your goals. Maybe you have an external deadline, like a test date. Maybe you are traveling abroad. You can also pick a time by which you want to have learned _________ .
5. Learn cognates
Learning cognates (and false friends) can speed up the learning process considerably. Learn the ways in which the language is similar to other languages you already speak, and ways in which it is different.
6. Practice a little every day
Practicing a new language is like practicing any new skill. You need regular practice. This can be 15 minutes between classes, or for over an hour. You can practice at home, or talk to yourself in the car, or listen to a podcast while you commute to work. It depends on your goals and on the time you are able to spend each day.
7. Listen, listen, listen
Watch movies and tv series, listen to youtube videos, put on a radio show, listen to a podcast. It isn't important to understand everything. You can put on a podcast and do other things like clean your kitchen or take a shower. Listening to the rhythm of the language can be helpful even if you don't understand everything that happens.
8. Concentrate on communication
If you concentrate on communication, even at the most basic level, grammatical structures will come. You learn to structure language best by USING THE LANGUAGE.
9. Use the target language right away
Speaking fluently comes from speaking poorly. Don't wait for your language skills to be perfect to practice, it isn't magic! Mix vocabulary and grammar you already know to use language creatively. Language is meant to be played with ;)