Raise the breast collar. Tighten the rear buckle one and the front buckle two,
Harness should be even on both sides.
Raise Tugs, What holds the shafts up, 4 or 5 buckles. They should follow the line your traces make from the breast collar to the cart.
Raise your breeching two holes on all buckles.
Loosen t Throat latch one buckle on each side.
Eventually you will get rid of the overcheck and get a real noseband. Try and find one.
That's a start
The best time to plant a tree was 20 years ago, the second best time is today.