Estelle In A Greenhouse

Nae: I was sketching one day, and I wanted to draw Estelle in the Greenhouse which she loves so much.
It was practice for backgrounds, which I'm horrible at. >.<
Chibi is so cute!
The outfit she's wearing is not a normal one she usually wears. Basically just made it up on spot.
Everything I draw looks slanted... Any tips to how I could fix that?
Any tips on backgrounds at all?