Apply powdered graphite between the floorboards and then clean up the floor surface with a damp cloth. Powdered graphite works into the floor seams better than liquid graphic, without the terrible mess liquid graphic leaves behind on your floor.
Listen for squeaks while someone walks on the floor above you while you are in your basement or crawl space. Look for nails that are rubbing against the floor joists, and cut them off with diagonal cutters.
Insert glue-coated shingles between the joists and the subflooring to stop the squeaks if you see gaps between the joists and subflooring.
Re-nail loose planks to stop squeaks coming from between joists, due to inadequate bridging. Strengthen the support of the subflooring by nailing solid blocks between the joists.
Apply wood glue if you can't get below the flooring to fix the subflooring. Squirt the wood glue into the cracks of the bamboo boards, and work it in with a putty knife. Thoroughly wipe up any excess glue with a damp cloth.