Before we moved and my oldest was in school, I would have time to catch some of the craft shows that PBS offers every now and then. One day I was watching a quilting show and found out about a way to ruffle I had never seen before. The lady said this is her most favorite way to do ruffles, and I have to say, I agree. Although I do think a ruffler foot does the best and easiest job of it all, but if you don't have that this is a good way. It just might not be a good option if you are putting the ruffle right on top of the fabric, as the zig zag stitch wouldn't look so pretty (unless you picked it out afterwards...too much time for me though!).
You start by pulling the top thread out and making it a few inches longer than piece of fabric that you are going to ruffle.
Just hold your fabric in front of machine as an easy length guide.
Next, put the long thread over to the side with the bobbin thread and sew just 1-2 straight stitches.
Now change your stitch over to a zig zag stitch.
Put your needle in the down position (so it's through the fabric) and put the sewing foot up. Pull the long top thread over the piece of fabric so it's on the edge where you are going to ruffle.
Put the foot back down and hold the top thread in place and begin to zig zag stitch overtop of it.
Once you get to the end, cut your sewing thread and then just pull on the piece of thread you zig zag stitched over.
You can pull it as tight as you need to. I liked how much more secure this way was. I have broken threads many times with the "make a long straight stitch line and pull on the bobbin thread" ruffling method. But you don't have to worry about that this way.
Give it a try next time you need to ruffle and see if you like it or not :)