it's nearly impossible to hang things on the wall.
things I have found that work:
double sided tape (and only if you're hanging like a single sheet of paper
gorilla tape (but it leaves icky black gunk behind)
electrical tape (see here)
and the humidity in Grenada is always your enemy.
I helped a friend hang some art up in her house & I think it turned out awesome!!
We printed pictures and letters out on regular paper (so it would be light weight & economical) and used ribbon to make make-shift frames!
and they're a pretty cute family so that always helps :)