Ideally, it's best to read the whole manuscript out loud. You won't believe how many things you'll catch that way! However, I don't always have time to do that, I'll admit…what I do try to check for is:

Typos and misspellings

Weak words, especially verbs

Awkward phrasing

Wordy sentences (This is my Achilles heel. Bet you couldn't have guessed that...)

Overwriting

Adverbs (Although I must state I have a great fondness for adverbs. But the strong, expressive ones, not weak ones. Although sometimes I thi