Whilst I hope that this post provides some tropical inspiration for you, before you go any further, I recommend reading my article: To Decorate or Not to Decorate. I sum up all the lessons I've learnt over the years in regards to setting up a classroom (Spoiler Alert: I haven't always gotten it right!) and tackle the debate surrounding classroom decorating! You can read the blogpost here.
These plates were used to cover up peeling and cracked walls.
This glitter foam was used to cover up cracked, peeling skirting. See the 'before' shot below:
Whilst I have since found less busy ways to cover up walls, this flamingo wall paper and tissue paper pom poms were used to cover up the wall below: