I had the BEST quilt teacher when I first learned to quilt. Besides looking at those sites, there is one other tip that is not mentioned. I iron one seam one way and the other seam the other way and then when I go to place the two seams together "you feel for the two seams to butt up together" then pin the seams on either side. It takes a little practice but I guarantee you will see that you have perfectly matching seams every time! Hope this helps.