Try to develop unique interpretations of the text for text response through just analysing everything that COULD have a deeper meaning (ie a LOT) and thinking about it whenever I can.
For language analysis, really you can only practise once you've got the technique down. So I guess make sure you're analysing at a deeper level than just acknowledging the use of typical 'persuasive techniques', try to incorporate a complex analysis of concordant devices and their intended effect on an audience. My biggest problem in LA is time, as my analyses tend to be far too long to fit into a 55 minute time frame.
Developing your ideas and, I guess, philosophising about your context will really help you write your context piece. Try to keep an either mental or physical note of real world instances of your theme, ie if doing 'encountering conflict', make a "conflict bank" of different ways people encounter, deal with, deflect, create, live after, suffer from conflict etc etc. Generating a profound knowledge of your context, and then seeing this reflected in your texts, will help you develop flexible yet detailed ideas with which to base your essays on.
Other than this - write, write, write! Reading A+ essays, study guides etc will help a little, but the number one way to strengthen ideas and your skill as a writer, is to put it into essays. Get your essays marked, mark them yourself, and just keep it up. You'll appreciate it at the end of the year! (And think, the better you get, the more efficient you get, so if you have to spend an hour and a half writing an essay tonight, you're giving yourself about half an hour's free time in the future when you've got to an hour-per-essay stage!)