For hiding threads by hand, you really need a cheater needle. Leah Day has a great video demo about this:
http://freemotionquilting.blogspot.c...g-threads.html
You can eliminate the need for this by taking 4 or 5 tiny stitches at the beginning of a line of stitches, and about 4 or 5 tiny stitches at the end of stitching. In this case you clip the threads close to the quilt. Experiment with this method to make sure you like it and that it works with your thread and design.