Crocheted fabric is begun by placing a slip-knot loop on the hook, pulling another loop through the first loop, and repeating this process to create a chain of a suitable length. The chain is either turned and worked in rows, or joined to the beginning of the row with a slip stitch and worked in rounds. Rounds can also be created by working many stitches into a single loop. Stitches are made by pulling one or more loops through each loop of the chain. At any one time at the end of a stitch, there is only one loop left on the hook. Tunisian crochet, however, draws all of the loops for an entire row onto a long hook before working them off one at a time.

International crochet terms and notations

In the English-speaking crochet world, basic stitches have different names that vary by country. The differences are usually referred to as UK/US or British/American.

Another terminological difference is known as tension (UK) and gauge (U.S.). Individual crocheters work yarn with a loose or a tight hold and, if unmeasured, these differences can lead to significant size changes in finished garments that have the same number of stitches. In order to control for this inconsistency, printed crochet instructions include a standard for the number of stitches across a standard swatch of fabric. An individual crocheter begins work by producing a test swatch and compensating for any discrepancy by changing to a smaller or larger hook. North Americans call this gauge, referring to the end result of these adjustments; British crocheters speak of tension, which refers to the crafter's grip on the yarn while producing stitches.

Differences between crochet and knitting

One of the more obvious differences is that crochet uses one hook while most knitting uses two needles. This is because in crochet, the artisan usually has only one live stitch on the hook, while a knitter keeps an entire row of stitches active simultaneously. So dropped stitches, which can unravel a fabric, rarely interfere with crochet work. This is also because of a second, perhaps less obvious, structural difference between knitting and crochet. In knitting, each stitch is supported by the corresponding stitch in the row above and it supports the corresponding stitch in the row below. In crochet each stitch is only supported by and supports the stitches on either side of it. If a stitch in a finished item breaks, the stitches above and below remain intact, and, because of the complex looping of each stitch, the stitches on either side are not likely to come loose unless put under a lot of stress.

Round or cylindrical patterns are simple to produce with a regular crochet hook, but cylindrical knitting requires either a set of circular needles or four or five special double-ended needles. And free form crochet can create interesting shapes in several dimensions because new stitches can be made independently of previous stitches almost anywhere in the crocheted piece.
Knitting can be accomplished by machine, while many crochet stitches can only be crafted by hand. Although some crochet patterns can emulate the appearance of knitting, distinctive crochet patterns such as the Granny square cannot be simulated by other methods.

Crochet is more suitable than knitting for joining pieces of fabric and knit patterns for sweaters may incorporate crochet for finishing. Crochet can add borders or surface embellishment to both knit and crochet fabric. Crocheted fabric uses 1/3 more yarn than knitted fabric. Crochet produces a thicker fabric than knitting, and tends to have less "give" than knitted fabric. And, generally speaking, crochet technique produces fabric faster than knitting.