This video demonstrates a very simple method of weaving in the ends of the yarn that are hanging out after you have finished knitting your garment. With the end piece threaded into a needle, bring it in one or two rows so it's not right on the edge. Then working up the row, weave the thread in and out of each knit stitch for an inch or so. Pull the yarn tight, then go one stitch over and work the yarn down the other side in the same manner, weaving in and out of each knit stitch. This creates a secure finish that is practically invisible and can't be easily pulled out.