Some are born that way and can come up with a creative campaign on the way to work, other's like to spend their time being inspired by the environment in which they live in, and of course, the one's who are time poor and like to surf the net, find the internet a great source for inspiration.
I personally like a combination of both and collaborative creative ideas always seem to draw the best inspiration from each of the different sources.
If you are looking for inspiration online, here is where I like to go:
This is a designers go to point for inspiration. Mostly the designs are clean and creative, and they cross many industry sectors allowing for creatives to be inspired by variety and relevancy which is very important.
2. Creative Boom:
There is a cross section of creativity on this site. It is inspiring and pushes boundaries while staying sometimes within the lines.
It's a strange phenomena to think that we have two sides of our brain that decipher information in two inherently different ways.
The left side is logical, analytical and objective, whereas the right side is intuitive, thoughtful and subjective. With the latter being the one credited to creativity; some of us are fortunate enough to play in a creative field where idea generation, designs and looking to the future are all part of the parcel.