The first thing is to relax and take it slow seeing as you're only in year 10. Make sure that you don't think of revision as an obligation. I can understand what you're saying about Spanish lol. In year 11 and it's my worst subject. I can give some brief things that you should try and get done as early as you can.
For maths learn all the content perfectly. Everything. Then just do lots of practice. Questions are questions so you can use any questions related to the topic. Just make sure you learn all the content. Less of a struggle in year 11. You can still learn all of the content quickly(I had to learn it all in 2 nights lol so you really have nothing to worry about). For English make sure you read your set texts as many times as possible. Memorise that s***!!! ...Nah you don't need to memorise them but if you read them a few times you should be able to remember lots of quotes by heart. Make sure you learn a lot of interesting context for all the texts as well. I recommend you to start making essay plans for each character, theme and even relationships between characters from now. When you have the time make sure you write some and get them marked by a teacher. For English language, I really recommend you watch Mr Salles and Mr Bruff on Youtube. Also, make sure you read a lot of books for the section Bs of the papers. For section B for paper 1, you should read a lot of books. I recommend reading a lot of fantasy books for this because they tend to be very good for this type of stuff. They are rich in vocab and if you read a lot of fantasy books you will end up emulating their work a bit. For section B of paper 2, you should really read a lot of newspapers. The Guardian, Independent, etc... whatever you do, don't read the Sun and other BS like that. That's pretty much it for English language. For sciences, the CGP books are your best friend. Make sure you buy the workbook too!!! It's pretty much all you need. Science is really crammable. REALLY crammable. If you want to make life easier in year 11, just start going through the guide bit by bit and doing all the questions on the corresponding page in the workbook. Seeing as you do Spanish as well, I have a few things I think you really should do. First of all, make sure you know those tenses inside out. I mean it!!! Second of all learn all the vocab. For vocab, all you need is memrise. The more you do, the better. Those are the 2 best things you really should do. Also, practice conjugating infinitives with all the tenses. I was a bit bored so I thought I might as well just tell you some stuff.