A few tips I've picked up.
1) Change the font. This practice can spice up routine reading, especially at the sentence level.
2) Read aloud, either by yourself or get someone to read for you. Hearing writing can help you hear unclear sentences.
3) Read backwards, from last sentence to first. The idea here is to get rid of the cohesive picture of your writing that you have in your head, and read for sentence-level clarity.
4) Highlight key sentences in each paragraph and put it into an outline. The best advice I have read from Tara Gray, using key sentences helps to provide a more global picture of your essay and makes you look for coherence. Be sure to organize everything with your working thesis.
