In my new tank my background plants are growing toward the ligh and leaning to the front of the tank. I am thinking about tying them back with fishing line. Is this the best way to do this?

They will always grow toward the light. You can try moving the light more toward the back of the tank.

while I agree with yoink in general,
many plants grow sideways to catch
more light then they would vertically,
so it does become a challenge to train
them to grow the way you want to.

water flow may influence
growth direction as well.

besides fishing line, you might want to
try aluminum wire used as a plant stake.