Do lots of comprehensions ! keep practicing them learn phrases for the letter so you can at least have some good german in them. like the greeting or closing look over vocabulary also in different topics ! Alles gute !
I'm doing my LC but I'm looking to do German in college , i think the paper is the same set up from what I remember . Aural listening offers a lot of marks so listen to radio stations in German , YouTube videos anything like that to get you hearing the accents .
The reading comprehensions are a pain , but try and practice them as much as you can :) highlight the answers in the text and number them to questions . Highlight key phrases in the questions to speed up your timing! Good luck , stick with Higher I think you'll be grand !