1. The One Crore Budget!
Many times we restrict ourselves to thinking about ideas with limitations of client budget or client not having the appetite or vision to spend that much. Though once in a while, go wild and dream - what if the client gave me One Crore rupees to execute an idea. This helps you break more barriers. Even more fun - after you think of the idea on this budget, challenge yourself if the same can now be executed in 1/5th the budget.
2. Idea in 20 seconds
Sometimes we have good ideas but we fail to communicate them effectively. At times we need to keep building on the idea to explain it well (or be defensive) either to seniors in the team or clients. One of the better ways to gauge your creative ideas is to challenge yourself to present it in 20 seconds. Much similar to getting your thoughts across on Twitter in 160 characters.
3. Socialise (Not media but physically)
It's important to socialise either formally or informally with different groups of people from various fields. Go join a Sunday morning walk in a group that may specialise in nature/arts/monuments/cycling etc. These are the places where you will meet people from different backgrounds and get an opportunity to talk beyond your office lingo. Eg you may come across a butterfly enthusiast who impresses you with knowledge and next you know you are creating an idea to publicize the "nature walk" amenity provided by a real estate client or promoting an "insect drawing competition" for the kids of a PSU client.
4. Be Fit
It's very generic, yet pertinent advice. You will be amazed by the kind of ideas that will start flowing into your mind if you are physically active and fit. I will tell you my secret - when I am on concalls, I do 3-5 sets of 15 squats each. I can never complain that I don't have time to be fit. Jog or stretch at your desk while taking a call or talking to a colleague, climb the stairs or play with your kid or a child for 30 minutes and see the difference it gets to a blocked mind.
5. The world is a theatre
Once in a while, try going to a mall or to the beach by yourself and act as if you are invisible to the world. Observe the people who pass by and notice what brands they wear, what phones they use, what foods they eat. Are they having a difficulty with their child, are they walking with their friends or elderly parents. Are those two girls in their twenties window shoppers, or is the guy who got off his Jaguar settling for roadside Bhel. The world is your research ground and these are the very insights you will use to trigger those fine ideas that will come back from the corner of your mind.