Make sure your invisible thread is the very fine monofilament thread which is almost like hair. The thicker thread, more like fishing line, will never work. Do not use the clear thread in the bobbin. Change your needle to a metallic or metafil needle in a size 14. Last tip, when I have really finicky thread I use a product called sewer's ease. It comes in a little bottle which can easily be confused with fray check. ( Do NOT confuse the two--the machine will not like it at all!) Squeeze a very thin line of sewer's ease onto the spool of invisible thread, about 3 times--three vertical lines of stuff evenly spaced around the spool. Let it soak in for about 15 seconds. Sew a little slower than usual and you should be good to go. The other tips about changing your tension should help as well. That sewer's ease is also great to use if you are having trouble sewing with metallic thread--like gold thread at Christmas time.