There are clear feet for the 9mm machines that help visibility and help hold the fabric on wide feed dogs Straight stitch throat plates help also, as do fine needles and fine thread. The perfect seam is a never ending challenge isn't it? I've been at it since the 2009 BOM and still trying. After reading a bit of Sally Collins' book Mastering Precision Piecing, I've started looking at every seam before pressing to make sure it's not wonky, so it's easy to unsew. She says to "analyze every step of the way & fix it before moving on." I find the biggest challenge in maintaining 1/4" over the spot where multiple seams meet. She also shows how to clip so pressing is easier. Oh, to be to her level of perfection, won't happen in this lifetime
I'm back to piecing on a 5mm machine with straight stitch throat plate, Aurifil, 75 needle and 1/4 foot, stiletto, and lots of patience.
By the way, there are great Youtube videos out on Leaders and Enders quilts that stitch up quickly when piecing other quilts, a great excuse to get an Accuquilt machine.
Having fun!