How to surface slip stitch to attach:
Surface slip stitching is a great way to attach straps to crochet garments, purses, bags, or otherwise. The surface slip stitch creates a very secure attachment and aesthetically pleasing stitch line. You may choose to use a separate strand of wool to stitch with, or if your fastened off yarn end is long enough, you may use the yarn end to stitch with instead (shown in video).
To begin mark where you want the strap attached, you may wish to pin or clip it in place, or place stitch markers at the position of the first and last stich of the strap you will be stitching through (shown in video). Slightly underlap the edge of the strap that will be stitched through on the wrong side edge of of the main part of your project. Surface slip stich across working through both the stitches of the main part of your project, and the edge stitches of the strap. Fasten off and weave in ends!