on Writing Forward:

Homophones are words that sound alike but have different meanings. They confuse readers and writers, and are often the source of frustrating spelling mistakes.

There are lots of tricks available to help you differentiate between homophones. In some cases, you can use mnemonics to remember which spelling to use. In other cases, you just have to memorize the words, their meanings, and their spellings.

In any case, it helps to understand the structure of language so you can more easily recognize words (including homophones) and how to use (and spell) them properly.

For example, knowing how to diagram a sentence and being able to identify parts of speech will give you an advantage when it comes to telling the difference between homophones.