If you want to create an outline using the thread/yarn method (called "cordonnet" method), here is how:
1. Put base fabric in embroidery hoop as support
2. Create a 'doubled' outline... That means for example, if you are making a circle, instead of making 'one line' with the thread, go around two times...
3. You can see this in this photo.Make sure not to have the ends of your outline thread at a corner in the design. For example if you are making a square, do not put the end of the thread at the corner of the square. It will just change the shape of the piece and weaken it when it's finished.
4. Tack your outline down onto the base fabric so it doesn't move while you stitch your lace.
5. Finished outline
When you start your filling stitches, start insided the doubled outline. Take your new thread and tie a knot at the outline.
Here are the finished stitches...
Now you finish the outline by using buttonhole stitches all over the outline. This will hold your lace stitches in place.
Cut the basting/tacking stitches on the base fabric...
Here is the finished needlelace piece. You can steam+iron it to flatten it down.