I was asked to do a pterodactyl... my friends son loves them. I found a color page of one and had it printed poster size. I was fortunate to have a poster printer available to me. Now I have it to size, basically.
Color pages are great to use. Find pics of basically what you are looking for and put them together in one picture. Go to your local print shop to see if they can put it together in a poster.
Hope this makes sense and helps.