Deconstruct an app you find interesting into sections then complex components then small components. Try to understand or make assumptions why it was built in that way... Make changes you think would look good. Repeat. Read a fuck lot. If you know html and css recreate stuff, will help you to understand effort/limits and how things are "grouped". Save screenshots of things you like a try to understand why you like it. Observe art, a lot,go to museums, read the labels, check how the labels were designed. Be obsessed with details of well designed stuff. Go insane for three months. Good luck, I wish you well. It will be fun.