Locate the exact squeaky spots by walking slowly and marking them
Tighten loose floorboards to the subfloor with screws
Drive screws into joists if the squeak is from movement between boards and framing
Use finish nails for minor loose boards, then countersink and fill the holes
Apply powdered graphite or talcum powder into small gaps between boards
Sprinkle baby powder into seams and work it in by stepping on the area
Insert shims between the subfloor and joists where there is a gap
Add construction adhesive to loose subfloor areas from below if accessible
Use a squeak repair kit designed for hardwood floors
Refasten loose underlayment if the squeak is from the layer beneath the floor
Replace damaged or warped boards that no longer sit flat
Secure the floor from the basement or crawlspace if access is available
Reduce humidity swings to limit wood expansion and contraction
Call a flooring professional if the squeak persists or the floor is heavily damaged