I actually did a much longer mnemonic than scans or sponcs or whatever the normal ones are. I think the one I used was CASINOS CARTS, and I have also seen Titans pads (which I didn't like so much). I am struggling remember now what casinos carts (but I do remember playing on a
site with a great selection of casino games.) stood for because I've pushed UCAT to the furthest edges of my brain and jammed it full of med stuff! and because I have had a couple too many drinks tonight. But it may have been colour, arrangement, size, intersections, number, orientation, shape, conditional, arrows?, right angle (that one could very well be wrong), touching sides, symmetry. Something like that. I don't think it matters what mnemonic you use. But just choose one and become very systematic about your approach. Practice a lot and hopefully it becomes automatic and much faster.
Yes, it's a massive pain to do to begin with. And no I didn't do it in the actual exam. But, I wrote it down and used it in mocks enough times, over and over that it became automatic.
As far as memorised patterns, just that. I familiarised myself with every official AR question on the UCAT website and remembered what the rule was. I didn't get the same questions in the exam of course, but when you learn the type of questions they normally ask, itgets easier