How to Hand Sew a Running Stitch
The running stitch is a simple hand stitch that is used for hand seaming, gathering and repair of machine-sewn seams. It is a small, even stitch that will look the same on the front and back of the fabric. The running stitch can be done with either a single thread or a double thread, depending on the strength needed and on whether the stitch is meant to be permanent (for example, often hand-gathering is meant to be removed once it's stitched down by machine).
The running stitch is a great stitch to know, especially if you have a "wardrobe malfunction" at a time or place when a sewing machine isn't handy.
Step 1 - Thread the Needle
For a single thread, tie a knot in one end of the thread, leaving the other end loose; for a double thread, knot the ends of the thread together.
Step 2 - Position the Fabric
Line up the edges of the fabric you're sewing; in the case of a hand seam, you will most likely be matching two raw edges of fabric, and in the case of hand mending a ripped seam, your seams will already be lined up for you and you will just be bridging the "gap" between the unripped portions of the seam. If you want to make sure you won't go astray, pin your pieces together and mark your seam line with sewing chalk or other washable substance.
Step 3 - Sew
Following your seam line, weave your needle in and out through all the layers of fabric you're using. Keep the stitches small and even, and check your work to make sure it looks the same on the back side of the work as the front side. You should collect several stitches at a time on your needle, then pull the thread through. This saves time and effort, and you can see how even your stitches are as you go.
Step 4 - Finish
When you reach the end of the area you're sewing, take a tiny backstitch and knot your thread through it to make sure your stitching won't come undone. Cut the excess thread off.
Basting Stitch
This is a longer and looser variation of the running stitch, meant to be temporary. It is used when you need more control over your fabric, for example, when it has a slippery finish and doesn't want to stay in place as it goes through the sewing machine. Another use might be if you're sewing a pocket into the side seam of a skirt, and want to keep the pocket piece in place between the skirt pieces without the bulk of pins. Basting stitches are meant to be temporary and are generally done with a single thread.
Saddle Stitch
Once again, this stitch is longer than the running stitch, and is used decoratively around details such as collars, cuffs, hems and the like. It is usually done with a thread that will show up well, in a different color than the background. Of course, when doing the saddle stitch it's very important that the stitch looks neat and uniform, especially on the side that shows.