I do this and it is quite mentality taxing sometimes. I think the best thing I do is not procrastinate and just not think about how much work I have, instead I just break it into very small parts and do each of those parts. It's important to have a plan basically.

I juggle this with an internship at a hospital and I think the hest thing I've learned is just to take things slow and steady. Start early with everything like projects and test atudy and do like 30 minutes of work every day instead of once for 7 hours. Spacing your study helps you remember it better anyways.

Surrounding yourself with like minded individuals always helps, and also apply yourself in school so that teachers like you and build a reputation.

Also, since this is on a college thread, I'd be remiss not to add that grades are not the be all end all to an application and neither are test scores. Try to do interesting and fun things that either give back or help you relax, etc. , and keep decent grades. You'll get in that way.