Canuck and 9fingerleafs said it right. Do it like skimming a boring book, hunting for key words. I like to follow each branch from its origin, and somewhere along its length, take one leaf. Preferably, where there are nodes with 2 leaves, take one of them. Go around each branch, systematically and do that one by one. That will help you go slow, and pick leaves the most strategically, and not get entranced to find that you've completely denuded her and stressed her to shit.
You can always go back and take more, but you can't put them back if you take too much.