Hi,
I haven't done a store before so I'm not sure about the categories.
To set your screen resolution, right click somewhere on the Desktop and a menu box will appear. Left click Properties, then click Settings. Move the slider somewhere between less and more under screen resolution. Mine is set at 1024 by 768 pixels and your store, the photos and the items look fine to me. Please proofread and fix your descriptions, though- some are hard to read.
Have lots of sales,
Bob