Some of the best advice is truly simple.
Read your work aloud.
This is classic, and a great technique for hearing the rhythm and flow of your sentences. It can also help you pick up repeated words or identify places where you’ve missed a word or a typo has crept through.
But there’s only one problem with this method – since you, the author, are reading the work, you may sometimes read what you intended, as opposed to what you wrote.
And so typos may slip through, missing letters or words too.
The easiest way around this is to have someone else read the work aloud – and the more unfamiliar the voice, the better. Some authors use their Kindle for this, others a variety of apps and Adobe Acrobat also has this feature for PDFs.
Obviously the voice that reads your MS will not sound truly human, but it will read exactly what has been written, allowing you to catch errors you might usually miss.