In poetic writing --
Refrain from switching from third to first person views.
Don't make the meaning or message too obvious.
(Unless that's the intention)
Don't obscure too severely or blow completely off track.
Repition can be your friend as well as your enemy.
(There's also a difference between repeating and reinforcing)
Avoid cliche, but embrace tradition.
Steer clear of an easy rhyme unless desperate.
The use of names can help or harm, depending on direction.
(Also changes by intention)
Stupidly long words can make it seem as if you're trying much too hard unless they flow smoothly.
Excessive gloominess or optimism can take poetry where it wasn't meant to go.
The main difference between poem and lyric is pronunciation and rhythm.
Personal poetry is often too muddled or revealing.
Allow inspiration, avoid imitation at all costs.
(Unless paying some kind of tribute where it is noted)
Pay attention to constructive criticism.