English Language

Don't worry about the learning anything, as such (I assume you mean mnemonics, rather than idioms?)- most exam boards discourage their use as they can make your writing disjointed if you're just frantically trying to fit in a semi-colon somewhere! Just practice timed creative writing and then go through and highlight all the techniques and punctuation examples that you used (perhaps highlight the first example of each technique in one colour and then any subsequent examples in another?) You can then look at your mnemonics and identiy the punctuation marks and language techniques that you have difficulty using and practice using them until you are comfortable, then write another practice essay and go through the same process again.

Thank you how can I highlight those techniques ; I didn't understand

Take a highlighter and literally highlight every similie you use, for example. You don't have to highlight the whole sentance, but just make it so that you can see how often you are using certaine techniques and so assertain which techniques you perhaps need to practice using a bit.