Cut your wood boards to the desired overall length and height for the lattice.
Prime and paint the wood boards on all sides and let them dry overnight.
Lay a yardstick out and position your horizontal lattice pieces against the yardstick. For climbing plants that require more support, such as grape vines and tomato plants, space the lattice pieces 4 inches apart. For plants that require less support and more open space, such as roses, space the lattice pieces 6 inches apart.
Measure down the length of the horizontal pieces, marking the equivalent measurement to the board's spacing. So if your lattice was spaced 4 inches horizontally, it should also be 4 inches vertically.
Lay out the vertical boards across the marked lines and drill a pilot hole through the top lattice piece slightly into the second piece.
Screw the top screws into position, then line up the boards for the rest of the screws with a carpenter's square.