When you shop for a frame for your new cross-stitch piece, take the stitchery along with you and compare several styles and colors.
Try several mats over your stitched piece to decide if you want to mat it or not. Keep in mind the feeling of your stitched piece when choosing a frame.
You might want to try an antique, time-worn frame. Whether you choose an old or new frame, a wooden frame with simple lines is usually best.