Portfolio Photography query

Try and make use of natural light as much as you can.

Set up near a window and experiment using a piece of card or a white sheet to reflect light back into the scene. Using a tripod and slow shutter speed can help you get a brighter image but can lead to overexposure. Try and avoid bright sunshine though as this can lead to harsh shadows or specular highlights.

I'd also buy a big piece of card or something similar to lay the designs on that gives you enough surface area that you aren't limited to how you compose the shots. Curving this up behind the scene can give you the appearance of a consistant background.

Alternatively, hire a pro photographer to do it :)
As above, just remember if you are shooting against a dark background, to set your exposure compensation to -1 or -2, so the images don't look washed out.