Hey man, some pointers on making this better:
-bright and bold colors are great, but they need to be used in moderation or it completely takes away from the realism. I would make the stairs and hubbas a different color and keep the planters the way they are. I would replace a lot of the colors with more nuetral ones.
-the layout could be improved by making it less symetrical and more complex and diverse. Get rid of some of the stairs and make some different features.
-its a school so make some buildings that are realistic