sail trim help

I love sailing but I'm NOT an expert , not even close.
My question is on sail trim.
The wind was 15 to 20 knots at times ( pushing up white caps in areas)
I have a small tell tail attached to the sail
1/2 way up the mast and one foot in from the mast.
while tacking, that tail always points forward instead of towards the back.
I know thats not right.
so , tighten or loosen out haul or down haul?
The vang is NOt attached at this time.
any ideas ?
My question is on sail trim.
The wind was 15 to 20 knots at times ( pushing up white caps in areas)
I have a small tell tail attached to the sail
1/2 way up the mast and one foot in from the mast.
while tacking, that tail always points forward instead of towards the back.
I know thats not right.
so , tighten or loosen out haul or down haul?
The vang is NOt attached at this time.
any ideas ?