Wall Sound Insulation

That might be a difficult one, it depends on how much space you can afford to loose to soundproof the walls, as @martin-f said earlier the simplest and most effective partic against impact noise is an independent stud wall, but you will loose 100 -150mm of space ..?

You say wooden floors, but is that just the surface finish, what are the actual floors made of, concrete slab or timber joists and are the neighbours floors on the same level as you , because if they are and timber you will probably have to do some floor soundproofing as well as it might also be coming in under the floor.

 

The flat has a concrete slab then floating floors on timber joists. I think next door fitted real flooring but didnt bother putting insulating membfane down first. What makes it worse is their shower pumps noise. So bad the council has banned its use from 11pm- 7 a.m.
The annoying thing is they are missionaries who arent interested in reducing the noise?
God does indeed work in mysterious ways it seems