In Rework and Edit, in the BBC’s Get Writing section, Barbara Trapido says:

Here is my best advice for editing and revising. READ EVERY WORD OUT LOUD.
Barbara Trapido, Rework and Edit

While the prospect of reading a full 100,000 word novel is more than a little daunting, the advice is sound. It’s amazing how clumsy some word groupings can be.

Even if you don’t read the whole novel, reading aloud just the passages you are having problems with can also help. 

You will find you skip words, or say them in a different order, or replace some words with others. If you stumble over words or phrases you will often go back and reword them so that you can say them, which you wouldn’t do if you were not reading aloud.

It’s a good idea to have someone else listening, or to tape your reading, so that they can pick up on things you don’t.

A truly useful exercise.