I also found it to help to make sure the knot is tied on the end closest to where it came off the spool. Proper lighting is a must also.
I decided to use the invisible thread to secure my squares in a Cathedral window I am making. HUGE mistake. It really knots and you may be half way around the squares before you see it and have to back track each stitch. I have no idea what made me use it but now I feel I have to continue with it. Never again.