Hi there, poets!
I hope to cover many many aspects of poetry writing here, but bit by bit and gently.
I am planning to give constructive criticism to help you improve on your poetry. If I can't be constructive, I will not speak, I promise!
There are many definitions of what a poem is. My interpretation is that it is the quintessence of an idea. There are many 'rules' to poetry writing, but every single one may be broken if your construction 'works'. Largely this is about what sounds right and what doesn't, and instinct plays a big part in this. What I hope to be able to do is to back up this instinct with some suggestions for what to do about it.
A thesaurus and a rhyming dictionary are both extremely useful tools for a poet to use.
Poems need not rhyme or scan, but they may do either or both. If they do rhyme or scan, care must be taken that they do not sound 'nursery rhymish'. If they neither rhyme nor scan, care must be taken to elevate the language so that they do not simply sound like prose.
For the first exercise, write a short poem about something you think beautiful. Pay careful attention to your choice of words. Make it as concise as possible by cutting out all extraneous words while keeping your meaning.