You are correct about pressing, and one last thought, press the piece first flat with both layers together to set the stitches, THEN flip the seam toward the dark side, UNLESS you are going to have problems nesting up seams later, this is why it is a good practice to make a test block first and see how the seams are going to go together best. It took me a long time to learn this lesson, but it is worth the time and fabric as it often uncovers other isues as well.
Pat