Double crochet is the basic and most common type of stitch that is essential to learn in order to do many different crocheting patterns. Structurally, it is taller, relatively solid, but less stiff than the single crotchet and is suitable for garments such as shawls, placemats, sweaters, afghans and many home decoration items. To achieve different patterns and desired textures, it is possible to combine the double crochet knitting style with other stitches, such as single crochet and half double crochet.
To make a double crochet foundation, there is a need to make two extra chains more than what is needed for a basic crotchet stitch. After that, turn the yarn back to front, similar to making another chain, but skip three chains, making sure to count the first, from the hook and insert the hook into the fourth chain. What this means is that there should be two chains skipped between the first hook and the second. Care should be taken to pass the hook through the V shape and under the bump at the back, avoid any twisting.
Then, hook the yarn and pull it through the two neighboring chains, leaving the first one untouched. At this point you have two chains at the end where you started, draw the yarn again through the new chain and the first one to remain with a single crochet like stitch that can be said to be two levels above the foundation chain. Go to the next chain on the foundation and insert the hook on the V of the chain and repeat as before. Continue with the repetition until you reach the end, or where the double crochet foundation chain started. If you count the stitches, the number should be less two on the foundation chain.
Once the end is reached, raise the chain to the required height by doing triple crochet up and turning back like it was down on the finished row. Count four chains and insert the hook on the fourth and draw the yarn through the two chains. After creating a similar double crochet chain to the one that was started with at the beginning, continue with the rest until the end is reached. Similarly to the first row, the stitches should be less two of the initial stitches.
Depending on the size of double crochet fabric that is being made, repeat the processes until the desired rows are knitted. Once the end of the garment is reached, fasten the yarn by making a knot stitch to prevent the yarn from undoing itself. To fully understand the process, practice physically as the instructions are read because it is easier to learn by practicing than by reading.