I just moved into this new high rise apartment and I'd like to hang
some stuff up. Mostly a few small paintings, but also a few heavier
(6.5 pounds/3kg) masks off the walls.

Anything wrong with the walls when I move out will obviously be my
fault, because the building just went up and I am the first renter.
So I'd like to minimize my visible exit damages to the drywall.

I have written down the paint color codes from Benjamin Moore for the
building, so I think I can touch up stuff when I leave.

Any suggestions as to what type of fasteners to use? And best ways to
fix things up when I leave? I've owned a house and am moderately
savvy about repairs.

In fact, let's extend the question all the way up to what adhesives to
use for my kids' posters. Ideally, I don't want my landlady to have
any excuses to bill me a repainting job.

Cheers