Via the Huffington Post, here's a post from 2014 that is still relevant: Nine Art Techniques That Anyone Can Do To Jumpstart Creativity.
I especially like the technique suggested by Martin Abrahams, Instructor of Animation at the School of Visual Arts. Here's his thoughts in his own words:
Doodle like a Traditional Animator.
"I’m always encouraging my students to understand the basics of traditional animation and apply them to your personal concepts, style, story or abstract ideas.
"It all starts with drawing. The rough idea of drawings, doodles, enthusiasm and sketches plays such a major part in the process of animation. We begin by drawing on paper and creating a personal stylistic approach, making drawings that move, a flow of story, design, animation principles, expressionistic style and content. The computers are there to make the finished film look colored and composited."
"There is no such thing as good or bad in art …it’s making it better. That's important. Take the principals and most of all give it your signature of personal style. Create images you want to see."
Martin's ideas can be applied to all types of art making. Make sure you read the complete article for more inspiration.