Baby powder, use a straw to eat into the seams.
They make a specialized screw called Squeek No More.... https://www.youtube.com/watch?v=d-4vibF9-f4 the screw top breaks off so you don't see it. Can also do carpeted floors. This Old House had an episode thats good for carpeted floor..... https://www.youtube.com/watch?v=4gUW-IhSMBc
You need to go down stairs under the floor and screw the boards in because the wood shrinks so you need to add more screws
Try these ideas to get rid of your floor squeaking....