I set the seam from the back. After that it depends on whether I want the seams to be open or to the side. All pressing is done with steam.
For open seams: after setting, I press them open from the back, flip and press the seam and the entire unit from the front. So the sequence is back, back, front.
For side pressed seams: after setting, I flip the unit face up seam to the left (I'm right handed) and run the edge of the iron along the ridge of the seam gradually moving it to the left and pressing the fold flat. I then flip it to the backside, press the seam again, flip it to the front and press the entire unit. The sequence is back, front, back, front.