Crochet stitches vary in height and can change the feel of your final project. Here are some of the most important ones to know (in US terms):

chain stitch (ch)

• foundation for most projects
• creates initial spaces for stitches
• used to create openings in a piece
• maintains straight edges when turning

slip stitch (sl st)

• shortest stitch
• technique similar to chaining
• used to connect stitches and create seams
• secures yarn when fastening off

single crochet (sc)

• height - 1 chain tall
• most basic crochet stitch
• creates sturdy fabric with small gaps
• good for bags, baskets, plushies

half double crochet (hdc)

• height - 2 chains tall
• uses another loop to add height
• creates looser fabric with larger gaps
• good for projects that need some stretch

double crochet (dc)

• height - 3 chains tall
• one of the taller stitches that is frequently used
• creates an open fabric with large gaps
• good for granny squares, filet crochet, and large projects

treble/triple crochet (tc)

• height - 4 chains tall
• tallest stitch that is frequently used
• creates a fabric with very large gaps
• good for creating interesting patterns and mesh fabrics

magic ring (mr)

• used to start projects in circular rows
• allows stitches to be cinched tight or otherwise adjusted
• good for plushies, granny squares, and baskets