A friend of mine told me a trick that she learned from a quilt teacher. Match up your intersections, pin, then sew about 5 stitches just over the intersection. Check. If its off, rip, and do over. This saves you from sewing the whole row and it coming out off. When you are happy with your intersections, sew the row.
Also, you will get better with time. It just takes practice, and one day you won't have to sew those 5 stitches, you will just have to pin, and sew the row. Keep at it.