I second the above post. I didn't think of getting the CGP revision guide for AS but it really helped me for A2 (Physics AQA A also).
I don't know how fast you can get your hands on that, but definitely try to get it because it will help for Unit 2 even if you don't get it by Unit 1.
Just work through the textbook and look up stuff that you don't understand from the book. I think there is a place online that kind of has condensed notes for Unit 1 - but I can't remember it off the top of my head, sorry.
Then work through past papers under exam conditions and look at the markscheme and learn from it too.
Don't stay up late unless you know it works for you - get at least 8 hours of sleep a day - I'm sure you'll be okay if you commit a fair few hours in the day and sleep properly.
So yes, just practice as many questions as you can from the textbook after writing out summaries from each page of the textbook and thinking about them, and then look at exam papers.
If it's any consolation Unit 1 was probably the most difficult unit in terms of adjusting to A-level. Of course A2 is harder but by then you'll be used to revision/past papers etc. I told my teacher a few weeks into teaching that I had no idea what was going on in lessons, and he suggested that I should keep calm, absorb the information over time and understand it.
The ISAs are also nasty, just look at past papers and see what they ask for. I really really hated them (I almost started crying in the A2 Chemistry ISA) and found the exam questions really tough, but somehow I got a B for the AS ISA (in a year 13 resit) and a C for the A2 ISA, so don't be worried if you feel like you've done badly, it might not be as bad as you think. I also mostly scraped As in the 4 exams, so I scraped an A by a tiny bit.
Good luck!