I tend to start working on an idea, then get another idea that I am more enthused about and start working on that without finishing the first. >.<' I also tend to go for projects that are way bigger than I can finish in a reasonable amount of time (this is especially problematic when I have to make something for arts class at school). Finally, I usually neglect working out ideas that would be more visually interesting (surreal) in favour of portraits/fanarts/comics, because the latter feel more 'meaningful' because they are based on something. This is a bit of a bad habit I think, because the more visually interesting pieces would be better art, especially if I would somehow manage to come up with a meaning for them.
1) I get a bit lazy with naming layers in Photoshop, though I at least remember to put layers in folders according to what part of the picture they're meant for. 2) I don't doodle as much as I should. I've gotten too obsessed with the idea of a finished product. 3) I'll occasionally try to add something that isn't really necessary because I feel like my work seems incomplete.
If you don't mind, samroxudont, I'd like to pass on some advice to you as well.
You don't need to work at huge resolutions considering the work you're doing is meant solely for publishing on the web. You could just work at a smaller size like 1000 to 2500 px but instead set your document to 300 ppi instead of 72 ppi (I'm assuming this is one of the problems you're having if you're making your canvases 10,000 px large). Then you can shrink a copy of the document down to 72 ppi once you have a finished product and save that as your final image. That way you'll have a smaller picture to upload while still having the original larger file to make edits to if you wish.