EXAM techniques

Hello, so I am an A2 student who is doing bio Chem and psych. My as results were BCB, honestly I was soooo dissappointed I honestly felt like I worked ever sooo hard and did well thought I would get 2bs and an a at least.. But now I feel so lost because I don't actually understand what I've done wrong at the end of a2 I want to pull each of my grades up but I honestly can say I can't focus.. I've been told to improve exam techniques but how do you improve exam techniques?? And how can I stay on top?? The fact that there are no jan exam is just scaring me!!!