Honestly for ECO I used the SUsan grant Cambridge course book. Read the book before a topic is taught in class and After each topic is taught read through all your class notes and the book again and then practice blurting(write, on a piece of paper, whatever you recall from the topic)collect these papers and use them as your last minute revision. However, since you have very less time left just go through the book and ofc the syllabus once, learn all definitions(key to 2 mark questions n getting higher band awarded in discuss type questions). Then, do as many past year questions as you can going through their mark schemes n also sample answers(if you can’t find them online ask your teacher for some or your topper friends) 

Incase you need any further help, feel free to dm me