1. Pin the right side of the bias tape to the wrong side of your fabric. Line up the raw edges as you open one fold of the bias tape. Be very careful not to stretch the bias tape as you do this. If you do, you'll be stuck ironing the item flat everytime you pull it out of the dryer. (Trust me, I speak from experience here.)
2. Stitch in the fold of the tape. I use an edgestitching presser foot to do this. It has a blade that will follow the foldline very easily. If your machine has a foot for making a blindstitch hem that may also work.
3. After you've completed the stitching, press the tape to the right side. This will encase all the raw edges making a very neat finish. The bias tape will conform to the curves in the garment as you press.
4. Using your edgestitching foot, sew a seam near the edge of the bias tape. Use the blade of the foot to follow next to the edge of the bias tape. Move your needle to the right and sew the length of the seam.
That's it. The project in the photo was the upper neck edge of a doll dress. The same technique was used for the hems of the girls' dresses. I ran out of the green tape for the hem of the doll dresses so I simply used white and reversed the first step and sewed it on so that it would be on the inside of the dress. If you're sewing in the round (as you would on a hem), start your bias tape with a small bit folded over on itself so you don't have raw edges showing. You can also get fancy and miter the ends together. I refer to a copy of Finish It by Alex Anderson when I need a refresher on doing that. If the ends of the tape will be enclosed in other seams (the neck edge of the doll dress will be enclosed in the bias used to finish the armholes) you don't need to worry about the ends.