Then comes the question of choosing a project you can complete with the sample. Motifs and bookmarks work great. Here are two of mine.
This one is a bookmark of Mary Konior's Duet pattern, made with size 20 Lizbeth #125 Seascape. I looove this color on the ball, but in this particular bookmark, not so much. Perhaps the back and forth rings were not a good choice for this thread. It looks better on Isdihara's blog.
I also used an exchange thread to perfect my koala bear pattern. I think this is Lizbeth 691 Mocha Brown Medium. It's a nice shade, a bit warmer than the similar Cebelia I had been using.
I've wound my shuttles with more exchange threads, so watch this space....
Later...by the way, I can claim this as Motif 20 in my current 25 Motif Challenge.