I'm thinking... start your dissertation early if you're doing one. Saves a lot of stress down the line and gives you some leeway if your first idea doesn't pan out.
Planning and preparation, make sure you time manage properly. Always be working on every unit, even if theirs no work due for a long time. Spend time reading and preparing for an assignment. Don't leave work to last minute. So far grades wise, I had my best grades in third year when it really counts, because of the above.