At first look your site has an overall professional feel, but there are some things that you should improve on.
You have a unique business, but the homepage is not. At first glance it looks like you're selling shirts, but nothing jumps out as custom. Your call to action, "design your custom dress shirt now" gets lots on
the red background because red is your main color. You need to make
your call to action stand out from everything else on the page, make it
the most prominent thing there is. Your whole objective is to draw people in directly to the shirt designer, so lead the way.
The red dv mark that's part of your logo at the top of the page looks really tacky. You should clean it up so it looks more professional.
The user navigation at the top right-hand corner: login, my account, and my basket are very hard to read.
I know you're using masculine colors, but reading white text on a gray background is really straining peoples eyes. It's best that you choose a dark text and use a lighter background color for the main body sections.