I am not a photo bod myself so couldn't possibly give any tips or such like, though I can echo what others have said in that you've obviously got a talent there
Not a fan of dogs per se so the subject matter isn't my thing but that's by the by...
If you haven't come across it though, have a look at
www.caedes.net and see if anything on there is any help. It's a massive photo site with some very very professional looking work (some not so), covering all sorts of topics, landscape, nature, portraits etc. etc. and it has a photoshopped section as well. I use the site mainly to see how much I could learn about photography when I get round to it and for setting my desktop backgrounds. It has a forum with lots of photo minded people for tips and such.
HTH