Leave it alone for a little while and then come back to it.
It’s always a good idea to come back to your writing after a couple of hours at least. That way you are looking at the content with a fresh pair of eyes and you are more likely to pick up on any mistakes.
Don’t rely on spellcheck.
Your computer will not tell you when you have used the wrong word when the word you have used exists. For example, you typed ‘cat’ but you were referring to a ‘cot’. It will not tell you that you have incorrectly used ‘too’ instead of ‘to’.
Go through your writing in different stages. For example, you can:
Print it out.
When you look at your writing in a different medium, you are more likely to notice typos and other errors.
Read it backwards.
When you read your writing this way your brain is less likely to autocorrect.
Read it out loud.
When you say the words out loud it can help you catch mistakes your eyes may miss.
Make sure you are consistent with names, spellings and certain types of punctuation such as quote marks.
Keep an eye out for variations on spellings and types of punctuation you may have used. Also, don’t forget to check that names are spelled correctly and the same way throughout your writing.
Ask a professional proofreader for help.
A second pair of eyes is always beneficial. Also, a professional proofreader has been trained to find the mistakes and make sure your writing is consistent in style.