The first thing I do is make sure all my blocks are squared up and the sashing pieces are exactly the size I want them. If I am using a 2 1/2" sashing I don't want any wings in the middle or curving out pieces. I then secure that first row with a few straight pins to the next row. The first row is always the most difficult. Then I keep building laying one row to the next. You will have more finished rows to to easily line up your quilt.