Abbreviations:

Back-Post Double Crochet: BPdc

Back-Post Single Crochet: BPsc

Chain: ch

Double crochet: dc

Front-Post Double Crochet: FPdc

Front-post Single Crochet: FPsc

Half-double crochet: hdc

Loop: lp

Repeat: rpt (often paired with *, indicating a certain point in row)

Round: rnd

Single crochet: sc

Slip stitch: sl st

Stitch: st

Treble crochet: tr

Textures are a way to give your project a really awesome flare to them, and I'll be showing the two most common ways: Front-post and back-post double and single crochet, as well as single and double crochet through the front and back loops, make it easy to spice up a bag or sweater sleeve. Before we start, here's a diagram of the anatomy of a stitch. Although this is double crochet, this goes for single crochet as well:

When a project tells you to Front-post single crochet or Front-post double crochet (FPsc/FPdc), it wants you to insert your hook into the post just below the one you're working on, facing you, instead of the previous "v" stitch. Think of it as crocheting parallel to the top stitch. Work the sc or dc as normal for the stitches indicated. BPsc and BPdc work the same way, except you single or double-crochet in the post away from you.

For crocheting through the front or back loops, only crochet through one of the legs of the next "v" stitch. If it's the front loop, it's the loop nearest to you. If it's the back, it's further away.