Hey, you are doing it very well, considering Dreamweaver is a new world to you and you are using an online tool.
Some tips:
1. Small fonts. Overall fonts are small. Put special attention on the fonts in your menu. They are not very easy to read.
2. Make your links more noticeable. They are light grey, and hard to distinguish.
3. Sizing info. Where is it?
4. Improve your photos. Many people need to see the closest to reality photo, in order to buy something.
5. Consider listing all your designs in one page, so users dont have to click through every tshirt.
6. Colors in your design. They should be the same in every page to keep consistency, as someone previously said. =)
7. White space. There's too much in some areas like in the right side of the pages, and sometimes in the bottom.
8. Make a logo for yourself! You are designers right? So why not making a logo for Two Souls that represents your way? You have amazing tshirt designs there, so go, make your logo!!
Good luck! =)