Insert you hook in next stitch in pattern (see below), yarn over and pull through both this loop and the loop already on the hook, just as you would if your were to work a slip stitch:
Repeat for each stitch across.
Make sure to insert you hook correctly in each stitch to preserve the stitch pattern. If, for example, you have been working in the Tunisian rib stitch, you would need to insert your hook from right to left for all simple stitches and from left to right for all twisted simple stitches:
