Third attempt... right but wrong

This is getting slightly embarrassing... My third attempt at the slippers failed again but I'm SO learning from my mistakes so it's good to hang in there and give it another try. This time, Tara from Mamachee, advised me to use four strands of yarn and hook number 7. It worked on the size: it's finally an adult size and I suppose the yarn I'm using is too thin to use as a single or double strand for these slippers.It looks OK though, but it's not and I know I'm probably messing up on the sole already as the heel doesn't seem to be in the right place. And since the heel isn't in the right place, the rest of the slipper is neither. By now, I must have done the sole five times and I really don't know what I'm doing wrong there. Its quite easy to follow the pattern but somehow I don't seem to end in the right place for the heel to start so all the stitches move a little bit and I get a crooked slipper.
I think I might need Tara's advise once more. She really should be charging more for her patterns with pupils like me! :)