I can't help with History or Biology but i did Psychology and English Language at AS last year.
Which exam boards do you do - it may help, i did AQA. For Psychology the thing i'd suggest is just to try really get an understanding of the topic and reading over notes before each lesson so your brain is always refreshed and ready and THINKING. For English (i personally hated it) but i'd really try to maybe do some practise paragraphs and just give them to your teachers to look at e.g. Practise using GASP and evaluating each thing - all subjects you have there are essay based (except biology) so the best thing to start improving is evaluative and analytical skills. However i really wouldn't worry too much about this at this stage it's all to be learnt, and the essays your getting back now will help you later in the year to see what you need to add - the teachers should tell you structures and points and help you out if you ask. But honestly the subjects are all hard (all alevels are) and it's only been a few weeks don't panic!! you'll progress masses soon enough - it's just the getting used to the AS level that is tough. I'm sure a lot of people are feeling the same and are in the same boat.