Rhyming pitfalls:
Bad rhymes: words which only faintly rhyme with one another, or have to be mispronounced in order to rhyme (eg squabble/babel). Don't be too proud to consult a
rhyming dictionary if you're not sure. (Note: Some would call these half rhymes, oblique rhymes, slant rhymes, near rhymes or off rhymes, and don't necessarily consider them a bad thing in poetry; I'm not one of these people, but given a choice, bad rhyme is always prefered to forced rhyme.)
Simple rhymes: Words that have been rhymed with one another countless times; usually the first rhyming word that comes to mind (eg when you hear cat you probably think hat, or bat, or fat). They are usually monosyllabic words with little if any emotional or intellectual connotation. Villanelles and children's poems are a little more forgiving in this respect (but that depends on the critic

).
Forced rhymes: This is basically when the poet has elected to sacrifice the content and/or the continuity of the poem in a line (or lines) just so that it will fit the rhyme scheme. Never use rhymes as an excuse for bad writing. Check
this out for more info.
If anyone has some advice on how to avoid these pitfalls, let's hear 'em.
Glossary of rhymes.