I think the best way to explain the logic behind my numbering system is to look at an example.
Here I have a design for a little fish.
So I have marked my sharp angles above.
Piece 2 is folded on the edge that is connected to piece 1. Here I would baste the other three sides first and then topstitch the folded edge (the bold line).
Here's a little exercise for you to try. Draw yourself some doodles. Mark the sharp angles and then start numbering the pieces. Usually one of the pieces in the middle is a good place to start. Imagine piecing this design and mark each fold as I have done in this example with a bold line or highlighter. As you mark each fold, make sure none of the folds are sharp angles. I must have done this about a dozen times on paper before I made the heart quilt I use in my profile.
More tips on piecing using the baste and topstitch method coming up as I continue with the gecko quilt.