Pay attention to the tone of the scraps. I usually sort light, medium and dark into piles, then attach a light to a medium, a medium to a dark, and a dark to a light to get the best contrast of the colors.
Take a look at your example. They used 4 dark or 4 light/medium in the center, surrounded by dark, light, light, dark strips for the squares, and a uniform medium blue/light blue for the squares making up the diagonals. The equilateral triangles around the border are all the same tone as well. That is what makes that design pop.
This is what I would consider to be an organized scrappy quilt, as opposed to one where you just grab and attach whatever color your hand has in it. It will take a bit of planning on your design board before assembling to make the colors blend the way you want them to, but the result is WELL worth it.
Good luck!