There’s a lot of deleting in copyediting, not just of the “very”s and “rather”s and “quite”s and excrescent “that”s with which we all encase our prose like so much Bubble Wrap and packing peanuts, but of restatements of information — “as estab’d,” one politely jots in the margin.
Much repetition, though, comes under the more elementary heading of Two Words Where One Will Do, and here’s a collection of easily disposed of redundancies. Some of these may strike you as obvious — though their obviousness doesn’t stop them from showing up constantly. Others are a little more arcane — the sorts of things you could likely get away with without anyone’s noticing — but they’re snippable nonetheless.
In either case, for those moments when you’re contemplating that either you or your prose could stand to go on a diet and your prose seems the easier target, here’s a good place to start.
(The bits in italics are the bits you can dispose of.)