In a nutshell, I consistently draw inspiration from Nature. Nature is my Pandora's Box of inspiration. Water--rain, tears, puddles, rivers, oceans, lakes, streams...so much! Patterns--in foliage, in sunlight and shadow, in repetition, in animals...If I had to pick one thing, I would say the ocean/beach. Even if I don't paint "it" per say, it calms me and makes me feel a part of something much larger. Then I can move forward and create. Unfortunately, being in the mid West it is not something I experience as frequently as I'd like to!
As for ways to push myself, right now it is the drive to succeed as a professional artist, so I set deadlines for projects and am constantly trying to think outside the box for marketing ideas.
doodling; trees; seeing a pile of stuff and catching something out of the corner of my eye.
Also, I write everything down and I have pieces of paper with great ideas on them (happily) littering my life...great ideas to find here and there and say, "oh yea!"
I usually walk around taking pictures of almost everything I find in my yard really up close, so when I need some inspiration i go to my pictures and something usually pops out. i also like to "doodle" and see if I can turn it into something coherent, specially when a painting comes out wrong. lately I've been taking a figure drawing class, and using the gesture drawings for inspiration.