Store the floor boards in the room where they will be installed to acclimate them to their new environment. This alone is usually enough to minimize warping and twisting. Let the warped boards sit for one to two weeks before installation.
Start the project with a few straight runs of flooring to give you space to work on the more warped pieces later. Use a rented power floor nailer. A power nailer has the strength to nail through the tongue and the subfloor, while also forcing the board tight against the floor.
Tap each board into place with a short piece of flooring. Use a hammer or rubber mallet. This helps get the board as close as possible to its neighbor to ensure a tight fit.
Step on warp or twisted boards while you set the power nailer in place. Having a friend on hand makes this step easy.
Screw down any stubborn boards that won't lie flat with power nailing. Screw drywall screws into the tongue in place of the flooring nails.