Capitalization and Punctuation
Capitalization and punctuation are the most basic of elements in a sentence; they tell us when it begins and ends.
Do and Don't
The vast majority of the time, standard punctuation and capitalization will work best. When you do experiment, keep in mind that most punctuation will control the flow or speed of the poem by slowing it down or pausing for a split second; use that to your advantage.
Ellipses (...) should be used sparingly at best. They
do create that sense of 'trailing off', but it's not very dramatic and the abrupt pause of a period -- or in some cases the hiccup of a dash -- might work better.
Consistency is key once again; your capitalization and punctuation should be done according to the same rules throughout the piece, whatever those may be. In a piece with no punctuation except one comma, for example, that comma is going to stand out like a sore thumb -- and hopefully hitchhike to somewhere else with it. Even most professional proofreaders won't pick on you for your commas, however, as long as your usage is -- you guessed it -- consistent.
Special Topics
Punctuation means
all punctuation, and we can play with it for several effects. I'm especially thinking of parentheses right now. They're excellent for setting up more layers of meaning. Parentheses make self-contained units within a phrase or even a word, and are used to set something apart from the rest. We block it off, and the reader reads the straightforward phrase and a 'hidden' second one inside.
Breaking the Rules
Removing punctuation will let the words and sentences blend into each other. This can also be great for creating double meanings or puns, but make sure it isn't at the expense of clarity.
Lack of capitalization will have the same effect, and might actually go very well in a piece already exploring the theme of freedom or boundaries.
Example
Poetess Laureate
She never leaned into its S
curve (except) with break(s)
-neck speed.
In the above, we have the plain "She never leaned into its S curve with break-neck speed" and "She never leaned into its S curve except with breaks" by the time we read with parentheses. The first tells us she doesn't take risks, the second tells us she'll stop short if she comes to something she finds dangerous -- similar but reinforcing messages.