Front and back post stitches are a simple way to add texture to a project and are the basis for crocheting cables.
I am using DC/TR to demonstrate but, as usual, the idea is the same. First off FRONT post DC/TR
Insert hook in to next space
And under the stitch and out the other side
Yarn over and pill loop back through
Finish stitch as usual
This looks good on both sides
Super, now BACK post DC/TR, this can take a little getting used to.
Insert hook from the front of your work
Over the post and back in the other side
Yarn over and pull loop up
Alternating between front and back post stitches can give some lovely textures to a piece.
I use this technique in my Bat pattern.