Note that when you are stitching, you should not see any thread crossing lengthwise between beads, hence the name "right angle weave".
It is sometimes difficult to master tension when weaving with this stitch. Practice will help you feel how much or how little tension is needed to make the beads lay correctly. Don't worry if your beadwork looks a bit "wonky" at first. With practice, it will even out. It is also sometimes more difficult to get an even piece of beadwork using single beads for each of the four sides of the units.