A simple tip for bracing wood that needs nailing
Nailing together boards that aren't solidly supported can be frustrating. The wood tends to bounce away each time the nail is struck, such as when nailing fence pickets to a horizontal rail or tacking thin wood trim to a lattice panel.
The solution is to hold a sledgehammer against the back side of the bottom board, then hammer the nail through the top board. The heavy head of the sledge will absorb the hammer blows, support the boards, and prevent bouncing.