Is this for GCSE or A level? I didn't do WJEC at GCSE, but I did study Of Mice and Men. I haven't done either of the other texts, so although I can't help you with tackling the exam or the likely questions, I can offer a few revision tips.
Firstly, the best way to revise for English (in my opinion) is to look at the major themes of the texts. You can start off by looking online, asking your teacher/classmates, or in a study guide - and think of some more if you can. Once you've got some key themes (and often they interlink, as is the way with literature), you can look at the parts of the texts which link to this theme. You could do this in any form you like: mind-map, list, cards...
You could also look at the main characters, something which is particularly useful at GSCE as there may be a question about a character.
If you have no idea where to begin even after that (or if you've finished doing that), take a look at some past paper questions. It might be a good idea to answer a few and get your teacher to mark them, so you can improve your technique. However, it may also help to look at what questions have been asked before and roughly plan what you'd write in the exam. If a similar question comes up, you'll be thankful.
I hope I helped - feel free to ask if you need some more specific help.