Print out a list of homophones.
Read through the list to familiarize yourself with the words. Use a dictionary to define any unknown words.
Create sample sentences using the homophones. For example, for the words "ad" and "add," you may write the sentences, "I saw the product in the ad" and "I will add the numbers together." Using the homophones in a concrete way will help familiarize you with the correct use and spelling, giving you a reference to draw from for future writing.
Mentally refer to the list of homophones, their meanings and the sample sentences you have created when writing sentences that contain homophones. If necessary, refer to the physical list of homophones and sentences to ensure proper use of these words.