Go online to sites such as Poetry.com, RhymeZone.com or Rhymer.com.
Type a word into the search box. For instance, type the word "monkey."
Click on the options below the word to get rhymes based on your preferences. For example, on Rhymer.com, you can click and hold the arrow in the option below the search box to get "End Rhymes," "Last Syllable Rhymes" and more. Each of these will provide different rhymes, depending on the word you typed in. Obviously, a monosyllabic word like "cat" won't produce as many options as a word with two or more syllables, like monkey, since there is no middle or last syllable.
Typing in "monkey," for example, and clicking on "Double Rhymes" gives several responses in which both syllables rhyme with those in "monkey," including "spunky" and "chunky."
Organize the results based on what you are looking for. For example, on RhymeZone.com, you can choose to see results organized by syllables or letters, and can also ask for phrases to be included.
For example, typing in "monkey" and clicking on "letters" offers rhyming words broken down into the number of letters in each word, from five to nine.