Hello Chelsea,
First of all use a good mercerised thread top and bottom, don't use cheap thread, don't use thread that is too thick, set the top tension between 4 and 5, make sure you can just pull the bottom thread through with some slight resistence, if it feels too tight slacken the screw on the bobbin case about a quarter of a turn anti clockwise at a time until the tension looks right.
drivewithken@blueyonder.co.uk, December 2008
