Bad: wonderful & dutiful, plenteous & egregious, bifurcate & allocate
Just read what you try out loud. If it sounds like it needs improvement, don't sell yourself short. Be patient; the right rhyme will come to you.
Subject & Voice
I won't devote too much time to subject and voice, because these things are so individual.
I once had an unassuming gentleman in old clothes and a leather jacket quote me the most beautiful rhyme I had ever heard about a tree. All walks of life produce good poets, and any thing can make an ideal subject. It all depends on your genuine knowledge of and interest in your chosen theme.
Who is the poem for? Children? Teenagers? Christians? Party guests? Knowing your audience gives you a start for finding the right voice. Party guests and children prefer fun subjects with a humorous voice. Don't rule out humor for religious groups, either. Just remember to keep it clean. Also, bear in mind the attention span of your target audience. An adult can read a lengthy masterpiece in segments of allotted time. A child, on the other hand, wants the whole thing at once, preferably in a very brief time-span.
Grammar
You have, no doubt, heard of poetic license. This involves the liberties taken by many poets with spelling and grammar. Remember the basic rule of poets everywhere: If it can be understood by the intended audience with minimal effort, then it works.
Whate'er my precious love desire
He will take tho 'gainst mine ire
The above verse isn't beautiful, but it makes the point. Grammar and proper spelling have always taken a back seat in favor of rhythm and rhyme.
Rules Are Meant To Be Broken
If you remember nothing else from this lesson in poetry, remember that if it reads well, then forget the "rules", for no great poem was ever written by somebody determined to go "by the book".
The following poems break rules, but they flow nicely. Try them and see.
The Blond
Blond hair
Never so fair
Green eyes that blaze in the sun
Beginning begun
Such is the end
My fair weather friend
Congress
Happy their smiles as they lower our taxes
Congress will listen, so they know what the fact is
