I start with a regular A2 size card front, often out of paper that is not my favorite, but sometimes just with white card stock (the heavier it is the easier it is to stitch through.) I take all my scraps and select five or six that coordinate somewhat, and I love ones that look like an old time fabric. I cut the scraps into squares that are 1 1/16th inch and then the fun begins with arranging them on the card front.
I keep the idea of a grandmother's quilt from long ago in my mind for inspiration (when they used to use up old clothing scraps.) I use adhesive to attach the squares to the card front. I try to put the squares close together so the paper below does not show through when it does not match, but sometimes it is nice to see a border around all the squares when it does match.
Then I use my piercing tool to poke holes all around the outside edge of the card, about an 1/8 inch from the edge. I also pierce holes around all the squares so that I can stitch between them (again thinking of the olden days doing hand stitching, so it does not have to be perfect.) The more holes you pierce, the more detailed the card will be.
Then I use embroidery thread to hand stitch around the whole thing. I love the variegated threads (if they match the papers somewhat) because seeing the lighter and darker shades of the thread adds to the texture of the card.
Have fun using up your scraps!