It really isn't any different than straight line quilting, just sideways! The difference is with the edges. So, for your first one (and to get past your fear) simply make regular rows , tilt them sideways and then trim the sides to make it square (rectangle). I know that sounds very simplistic, but if you do it with a small quilt, you will see how it goes together and then you will not have a problem working on a larger one.