Review the Prompt
One strategy for revision that may help you is to highlight the different points of the prompt in different colors. Then use those same colors to highlight the sentences in your response that relate to those parts of the prompt. For example, a prompt may ask you to describe an award you received, what you did to earn it, and what resources you used to achieve success. You may mark any ideas in your writing that relate to the purpose of the award in yellow, the narrative/process sentences in green, and the resources in blue. This will help you recognize if there are any unmarked sentences that might not address the prompt. It can also help you to see if ideas are repeated or underdeveloped.
Because personal statements are often limited in terms of character or word count, you want to be sure that you get the most impact out of the words you choose to use. Choosing a word that is more precise in its meaning and connotation will help you to use the space wisely.