I can't say much cause you are further along in the process then me, so congrats
-Your menu buttons need a vertical style if they are going to stay vertical...they currently are for horizontal menu bar.
-Your logo (TSC at the top left) should stay the same size when changing pages.
-The same logo should be a link to the home page
- Your Thank you for your business sign at the top right could/should be uniform.
-When clicking on a shirt design on details tab it takes way too long to bring it up, load, and become ideally viewable for the user...it should not take longer then 1 sec to enlarge the image..(do it like the Coming Soon image..that is quick to enlarge...still 3 secs to unblur image)
-i would bring the phone number and facebook id off the bottom of the page..I didn't notice it the first dozen or so times i clicked on contact.
I like the simple color scheme..though I am using a similar (same colors but white isn't the main) color scheme for a wholesale site I'm developing.
My background is in programming, web development, testing, user experience and I am trying to pick up screen printing as a hobby(if I'm any good at it I'll go from there

). You are way ahead of me so take my thoughts to heart..or as a grain of salt...hope they help.