1. Don't party/drink too much or too hard.
2. Keep track of everything being learnt in class. You won't be good at all subjects, but with enough effort you can pass and even do well in courses you didn't like.
3. Have a good network of friends in all of your classes. This can be incredibly useful if working on tough assignments, practicing on past exams etc.. Most professors are lazy and don't bother changing exam questions every year so you will probably end up with the very similar exams as previous years, so make sure you do them!
4. History is not a very employable degree. And at least in Canada, teaching is not easy to get into. You are better off going into Science, Business, Economics etc. I only know one History gradb and he's struggled to find a job for the past year. All he's found is a 3 month position at a museum on the other side of the country! Again, Canada might be a very different job market than the US, but make sure you research employment opportunities well. Try to get any work related to your field like internships before graduating. s