The front post double crochet (fpdc) can be used in a pattern to add texture or even to work crochet cables. Once completed, it creates a stitch that stands out from the background.
I use the fpdc in the Squishy Squares blanket pattern.
The full written instructions for the fpdc are: yarn over, insert hook from right to left underneath the post of the next stitch, pull up a loop, yarn over and pull through two loops on the hook, yarn over and pull through two loops on the hook again
Step One – Get ready to make the fpdc at the appropriate place in the pattern. In the photo below, I have just worked a series of regular dc, and I am getting ready to do a fpdc around the next stitch:

Step Two – yarn over and insert the hook from right to left underneath the post of the next stitch

Step Three – pull up a loop

Step Four – complete the dc in the normal manner – yarn over and pull through two loops on the hook, yarn over and pull through two loops con the hook again

A view of four fpdc alternating with regular dc:
