I also did a tutorial on making pom poms, just using your hands and a sharp pair of scissors. No gadgets necessary! You can check it out HERE
The key to a good solid pom pom is to wrap the yarn A LOT more than you think you need to! When you think you've wrapped enough, wrap some more! Also you must plan on trimming at least 1/2 to 1 inch off of your pom pom to get it to look tight and full. And you must also tie it very tightly across the middle. I find wrapping the yarn around once before tying makes it easier to get it tight. Also have someone put their finger on the knot while you tie it so it doesn't come loose as you are tying. HERE
is a project I did where the pom poms turned out great (I thought anyway!).