Hi
Here is just my thought:
The footer is mis-align using firefox
The menu wording eg "View our 123 products", which is in gray, doesn't look well with background.
Your theme is clean and neat.
But, normally if I am going to buy any template, I wanna ensure the store that I visit can impress me with it own store front first. Yours don't impress me.
Just get start with your business, and fine tune alone the way. You will never have a perfect design.
Hope for your very best in your venture