This list from Eric Kim is pretty good for people wanting to stretch themselves. And as is often the case, most of them can be applied to the rest of you life, even the seemingly technical things like “stick to one lens”. Here’s the list:

1. Focus on geometry
2. Be patient
3. Travel
4. Stick to one lens
5. Take photos of children
6. Be unobtrusive
7. See the world like a painter
8. Don’t crop
9. Don’t worry about processing
10. Always strive for more

via Kottke