It might help a bit if you told us if you are using a long arm or a domestic, what thread in the top and in the bobbin and the size needle. Our suggestions could be a bit more helpful than. On my domestic, I can use a good quality cotton thread like mettler or Aurifil but on my long arm, I like using a poly thread like Superiors 40 weight OMNI or Superiors 50 weight SoFine .