I used to write in chronological order, and will still even try to start that way on occasion. I stopped this because I would get stuck and not be able to get past a spot or want to change something and have to re-read/write so it didn't mess up any continuity. I'm super anal while putting a story together. For this reason...

I usually just end up writing whatever I feel. It could be the important stuff in the story, or it could be random filler stuff. It could be dramatic, action-packed, or fluffy. My notebooks are a disaster, and if I ever manage to finish a cohesive final draft of anything, my life would be complete.

I always plan out the story before writing, and that's rarely in chronological order. Usually, I come up with the beginning and the ending, then work out the middle before and while I'm writing the beginning. Usually, that comes randomly.

That's how I write but my brain does the exact opposite. I'm always planning new chapters.

I find it easier not to contradict myself or mess up the continuity if I write in chronological order, but I do write out of order from time to time, whether it's because I have an idea for further down the timeline that I don't want to forget or just because I'm bored/frustrated with the current action.

I tend to get the rough basis down in chronological order, during the planning stage, but after that I go backwards and forwards and just try to get things written down as soon as I know how I want to word it (before I forget!). That's when things start to get chaotic...

Sometimes if I'm at a stuck point I'll work on other chapters though.

I write random drabbles instead of proper chapters. Mainly because I don't publish my stories anywhere. xD