There is also a silicone product, called Sewers Ease or a similar name, that you can apply sparingly to the spool. I use just a thin line down the length of the spool. This will need to be done several times as you sew as the thread with this coating gets used. Also loosen the tension, which sometimes needs to be A LOT looser. A thin thread in the bobbin is also helpful.
Good luck
Laurie