For the geometry part, I would recommend drawing everywhere all over the question paper, draw in all equivalent sides, draw in all parallel lines and all equivalent angles. See if you can use any circle thereoms or trig ratios on them. Work out every side one by one. I find it also helps if you don't spend too long on a question, if you just don't see it, move on and come back to it with fresh eyes. Doing the past papers on the website also helps.