is it best to split Macbeth quote into themes or chracters

I have my English gcse in may, i would like to know which is the best method in arranging quotes

I would say to be safe, do both. I like to have about 5-ish quotes per character, and then again 5-ish for the major themes: when I say major, I mean the ones that are really prevalent, like Appearance vs Reality, Gender, the Supernatural, and Divine Right of Kings. It feels like a lot but the problem is is that the examiners often find a way to surprise you with their questions. In covering major themes and characters (only do main characters though, exclude minor ones like Fleance, Siward, Malcolm, etcetera haha) you get a wide range of quotes that, importantly, you can apply to a wide range of questions - and it lets you respond quicker to a question - if you get a question, for example, about the Divine Right of Kings, it's going to take you a while to go through all your characters to find quotes you can use: if you have already revised specifically for that theme, it saves you a tonne of time (and stress). Hopefully that makes sense, everyone's different, but those are my recommendations, and what I would say is safest to do.
Hope that helps! Good luck with your exams

P.S. if you're ever struggling to find quotes and need some speedy ones, feel free to post another message here, or DM me, because it can be a pain.