I agree with the others, but have one other suggestion. For me, switching to a thinner thread for piecing made a big difference, especially when sewing with some of the thicker fabrics, like Moda for example. I use Aurifil 50 weight, 2 ply for most of my piecing, especially in quilts with many small pieces. Each seam eats up more fabric. It is strong even tho thinner than your standard 3 ply. There are other fine 2 ply threads available, too.
Sometimes, pressing your seams open will make them lie flatter, too.
Hope you find these suggestions helpful. :)
Happy sewing,