I lay out my pieces, get them how I want them, then start top to bottom on 1st row, pin it with one pin. I do the same thing with each of the rest of the rows only the 2nd row gets two pins on the top block, 3rd gets 3 and so forth. It's pretty difficult to mix them up that way as you're only working on one row at a time and taking one block off the pin at a time after sewing the first two, keeps me right on track! I work in a very small space, so doing it this way really helps and is easy on the budget. Good luck!