well, I suppose the really good ones are no screenshots but simply renders.
But you can switch the grid off under display/grid And for the texturing under your texture node there is a little field called Hardware Shading(or texturing) which determines the quality of your texture while unrendered.
All you need to do now is take a screenshot. There are other ways too, like using the hardware render buffer (i think somewhere under window/rendering...) Or playblasting.
Oh and for white background, click on the camera you want to render from, go to environment in the atribute editor and ther you can change the background colour.
Have a look what suits you best
good luck with your wip