Start by reading the work of the many poets here, comment on them, and post your own work to receive comments from others.  Members here are willing to assist as far as critique and instruction/helpful hints for writing in general. Here's some further suggestions:

Poetry Workshop
This forum is a great place to ask for advice and discuss how to improve your writing.

Honestly Crafted Critique
This group is the place to request and discuss critique.

Yes - I want honest criticism
Selecting this commenting preference, when you submit your work, encourages other members to give their honest opinions.

Socialize
Connect with other members with a view to collaborating with them, for example, working together on a jointly credited submission.