i have finished my a levels.
my advice to anyone who is about to start as year or has just finished it.
Use the summer holidays to your advantage to work, okay by all means go on holiday and rest but try and prepare for the next year by doing notes etc.
In my opinion you could self teach your self about half of the content you will learn through your teachers. Also September to December is important if you haven't done much in the summer.
January to june should be used to memorise and to go over things you may not have understood before
ps i did physics maths f .maths and chemistry so can't really speak for econ or languages.