1) homework: Make sure you prioritise your homework and get most of it done when you get it! I know it is a lot to ask after a long day of school, but this means that you have more free time at weekends or in the evening. Personally, I have a pile of homework I haven't done and a pile I have completed so I know what I have done and where it is. This really helps me as I always want the need-to-do homework pile to disappear!
Sleep: Now I know some times it's hard to sleep well at night and get the appropriate amount of sleep. But it really helps! It gives you a higher level of concentration and helps you focus. You should get atleast 8 hours sleep per night. To get to sleep you should stop going on your phone half an hour before bed and stop drinking caffeine before bed. Also, you could try a scented mist or some relaxing music to help relax or calm you.
Try to think positive: If you always think negative you will get nothing done properly or to a standard you would like. To be honest, I'm not in the best mind set at the minute and I have noticed that my work standards have gotten lower! Please talk to someone if you are feeling down or stressed as they can help!
If you have a lot of work and want to organise and prioritise, you could draw a big timetable. This would include how many hours of homework you would do, hobbies and then some free time. This is helping me at the moment be less stressed and it is giving me more free time as i don't do too much homework at once.
I hope this helped with a few things! If anyone wants any more advice on certain things, please don't hesitate to ask me on twitter (@FallingStxrs)