Welcome! Do you know of the Austrian painter Robert Schoeller? I used to manage him until 1993. For several years running, he did the Donauinselfest (spelling?) poster and, in fact, I was in two of them.
There is a section on this forum just for critiques. Take a look for that and post there to ask for a critique of your work. This section is just for saying hello and letting us know who you are, so most will avoid critiquing here.