http://www.printablepaper.net/ where you can actually download .pdf files of octagons, hexagons, and diamonds. HERE is the link for the one I use. Print it on cardstock and you have your own templates. Now cut out a piece of fabric that is about 1/4" or a little more larger than the template.
This one is a bit ragged, but it doesn't matter, as long as it is big enough to baste down on all sides. If you are new to this, you may want to use a small pin to hold the paper in place.
Begin to baste by folding down one side of the fabric over the paper template.
Now you begin with a threaded needle, make sure your thread is knottted at the end. While holding it paper side up, with one side folded, you come up through the entire thing from the other side, You want the knot to be on the fabric side.
Now you go back down like so. At this point you want to stop and fold down the next side.
It is important to come up again right beside the fold.
Now you go back down again to baste the fold into place. After this you will take a couple of basting stitches toward the point, but not too far. You don't want to get under the next fold.
Here is the next fold. There will be a chicken-head looking thing sticking out. That is what you want. Once more you want to bring the needle up beside the fold.
Now you go back down again toward the point, to baste that point into place.
This is what it should look like. You still have that chicken head. After this, you simply continue around the diamond.
You will finish by going through and turning the diamond over, so that you see the fabric side only. You will then make a knot or take a couple of big stitches to hold it in place. Keep in mind that you will need to remove the knot later from the fabric side, so it is good to have that knot on top.
This is what mine looks like on the paper side.
And here it is again on the fabric side, complete with two knots.
Here are a few more. You may find it helpful to use a single hole punch on your templates to make them easier to pop out of the fabric later. I have done that in the past as you can see, but don't do it on my newer templates.
Stay tuned for part II, where we will begin to stitch them together.