Really struggling with AS Geography?

I got a B at GCSE but am really struggling with the jump. We are on OCR but I haven't yet got a text book because my school is considering changing to AQA (the same as the GCSE exam board).
The topics we're doing are -
River Environments
Coastal Environments
Hot and Semi-Arid Environments
Urban Change
The Energy Issue
Growth in Tourism

I'm consistently getting the lowest grades in the class and was wondering if there was any good revision sites to be looking at? Or just tips in general? I really love geography and I don't want to end up failing it.

When I did geography A level i did OCR board and it is the best i think for A level especially A2 so i hope you stay on it. I'm studying geography at uni now after getting B at A level overall (A for AS).
I also did all those topics apart from rivers.
anyway, i wouldn't worry about the textbook quite yet, although if you feel you don't know enough content then you could always buy one yourself off amazon, i think you can get 2nd hand copies fairly cheap. my advice to you is to not worry about getting lower grades first off, you are only a few weeks into AS geography so can't be expected to be A grade all of a sudden. what sort of grades are you getting?
try and get a basic essay structure in your head that you can use for every 25 mark essay you do, i remember being set my first 25 mark essay and having no idea how to answer it, my teacher gave me a idea of a structure for one and i found them easy after that. I have loads of my old AS essays still so if you want i could PM you and discuss how to structure an essay that will get you at least an A. often you feel you know what to write but just not how to write it.

If your problem is not understanding some topics or not knowing enough information or case study material then, i would get a textbook or a study guide for your exam board for you to refer too for help. but remember geography is not the study of the textbook it is the study of the earth so get case studies from other sources than textbooks, i didn't do this so much at AS but loads at A2 but i see no reason why you couldn't for AS. I write a Geography blog and a lot of my articles are based on essay questions and topics from AS and A2 geography so i could post a link to that if you like! (shameless plug i know ).

It would be great if you could post a link! And I've been getting either U's, Ds and the occasional C. Like as you said I know what I want to put but I have no idea how to actually explain it!