okay...you're gonna have so many different suggestions..you will have to try them... I cut pcs apart after seaming, (in this case, magic squares), place all pcs on the ironing board with the dark side up...this saves movements...press on top of the seam (setting the seam) to set the stitches... then open by holding the corner of the darkest side and press TOWARD the seam...this will automatically push the seam to the dark side... the 'setting the seam' creates a sharp line to fold on... it is really helpful, do not skip...
then i grab another square and place on top, starting the whole process again... after pressing 5 pcs (all stacked up) place them to the side (this helps count when you have a lot of pcs to press).