Retrac (note: it's 'Carter' spelled backwards) are 12 lined poems with an AabbccccbbaA rhyme scheme. The capital A is the refrain. Sounds simple, no? Well, you have to count your syllables per line.
Here's a somewhat helpful chart to guide you with that:
L1: 2 syllables
L2: 3 syllables
L3: 4 syllables
L4: 6 syllables
L5: 8 syllables
L6: 10 syllables
L7: 10 syllables
L8: 8 syllables
L9: 6 syllables
L10: 4 syllables
L11: 3 syllables
L12: 2 syllables (same as your first line)
So recap. 12 lines, AabbccccbbaA rhyme scheme, syllables going as such: 2, 3, 4, 6, 8, 10, 10, 8, 6, 4, 3, 2. And, though this isn't necessary, the poem looks much better when it is centered.
Examples:
http://allpoetry.com/Poem/1095758
http://allpoetry.com/Poem/1064812
http://allpoetry.com/Poem/1065802
You can also check out my old Retrac contest and read some of the entries. Believe me, there were a lot of good entries there.
http://allpoetry.com/Contest/1061618
The Retrac will take time but once you get used to it, you'll probably be all right
~CTHow to write a Retrac, a poetry form I cam up with.

