1. Put a new needle in before you start to adjust the tension.
2. there are two thread tensions on a normal sewing machine, top and bottom. If you can see the loops on each stich more at the bottom (or top) of the material proceed as follows;
3. tighten the top tension or loosen the bottom tension a tiny bit and check the result. (vice cersa if the loops are on top)
4. I spent 10 years servicing sewing machines. It is a bit of an art, but if you keep trying you should get there, however PLEASE change the needle first - that is the most common problem with all sewing machines. Good Luck
Simon, March 2006