There are several good Instructables with crochet patterns that show you how to use granny squares to make afghans, hats, scarves, bags etc. However, I did not see one on how to make a granny square. I hope this Instructable will fit the bill. It will teach you how to create this basic shape. There are lots of pictures as well as a detailed video describing the process. Please feel free to contact me with any questions you may have. Good luck!
If this feels a little overwhelming, you may want to start here to learn the basic crochet stitch. This is an instructable I made for those who are just discovering crocheting.
Step 1: Making the First Round - From Slipknot to Joining
Make a slipknot with your yarn and insert the hook into the knot.
Chain 4 stitches.
Insert your hook into the first stitch (closest to the slipknot).
Yarn over and pull the yarn through the stitch. Slip the stitch through the loop on your hook.
This creates the ring (center of the granny square). Take note of the hole in the center of the ring, this is where all the work will be done for the first round.
Chain 3 stitches.
Double crochet into the ring
Double crochet into the ring again.
This set of stitches is the first "shell" of the granny square. A shell consists of three double crochets together in the same space. Please note that the chain of 3 takes the place of a double crochet.
The first round will consist of four shells. You will need to chain 2 stitches between each shell in the first round.
Chain 2 and make another shell by doing three double crochets into the ring (this is shell number 2).
Chain 2 again, make another shell by doing three double crochets into the ring (this is shell number 3).
Chain 2, yet again, and make the last shell for round one.
You now have 4 shells and are ready to join them together.
Chain 2 stitches then insert your hook into the second stitch of the first shell you made (the second stitch on the chain 3 we did directly after making the ring).
With your hook through the stitch, yarn over and pull through. Slip stitch through the loop on your hook.
That concludes the first round. All subsequent rounds are just a repeat of this round. The only difference is the number of shells you will make and the amount of chain stitches between shells.
Step 2: Round Two
The first round of the square is complete. For round two start by simply chaining three stitches straight up.
Double crochet into the large hole near the base of the 'chain three'.
Double crochet again into the same hole. That makes three double crochets or a "shell".
Chain one. You only chain one between shells on the edge of the square. You chain two between a group of shells in the corner of the square.
Create another shell in the next hole.
Create another shell.
Repeat this pattern until the round is complete.
Join the first and last shell as shown in step one.
At this point you could keep going with as many rounds as you want, or you can finish the square off as it is. See step three for finishing off and sewing in the loose ends.
Step 3: Finishing Off
In my example above I have added two more rounds to the granny square. You can add more or less, it is entirely up to you.
Once you have completed your last round, cut your working yard, leaving six to eight inches of yarn.
Pull the yard straight through the last slip stitch you just made. This will bind it off and keep it from unraveling.
Now to sew in the loose ends. Use a large needle and thread the yarn through it.
Insert the needle through several groupings of loops. Pull through and repeat several times. There is no magic formula for this step, just sew it in discretely. When you are done, pull it tight and cut it off.
Repeat the same step for the other loose end.
Congratulations, you have completed your granny square. I hope this helps someone out and if you have any questions, please feel free to ask. I will help in anyway that I can. Also, I would love to see pictures of any square that you make.