How would you reduce noise from washing machine during spin cycle

Making sure the washing machine is level and all four feet are touching the floor helps to reduce noise, Use a level and adjust the front feet by turning them in or out with a wrench, also make sure you dont overload the washer.

also an even load of washing i.e. if you have a full load, dont put all the heavy stuff (jeans, etc.) at the bottom, spread it out.
Secondly, I had a machine that was under a counter and it used to move slightly and touch the sides, my solution was to put a sponge, a cheap thing from the pound shop will do, on either side of the machine, and these acted as a buffer between the machine and the side wall of the press.

as you say its an older machine i think you should check the bearings in the drum are not worn out this can cause lots of noise in the spin cycle. open the machine door with no washing in it and push on the top of the drum and see if its rocking up and down lots.

sounds like the bearings on the drum are on the way out
as they wear there is more play in the drum causing it to shake and vibrate more
eventually it will just stop, they can be costly to replace
but that's the only way to reduce the noise