The Round (or French) heel has always kind of bothered me. Just like with any heel turn, if you get off by one tiny stitch when you start the turn...well, you're going to have to pull it all out and start over. WAAAAY too much pressure for me, on some days.
I just found a cheat to make my heel turns (almost) foolproof.
Before you start the first heel turn row, place a marker dead-center in the middle of your heel stitches (that's the gold marker). Then, place another marker 2 stitches away from it, one on either side.
Knit over to the last marker, ssk, k1...
Turn. Purl over to the (was the first, but now is the) last marker, p2tog, p1...
Turn. Then just take out the markers and continue as you normally do for this sort of heel, secure in the knowledge that your first two rows, at least, are correct!
Voila. Heel turn courtesy of me. Amazing stitch definition courtesy of Simply Socks Yarn Company and some amazing Minnesota sunlight.