It is rare for innovation, change, or new ideas with staying power to develop on demand. Either people aren't ready to hear about them or the appropriate context hasn't been prepared for the idea to develop and mature. Coming up with concepts or thoughts on how to improve something can be easy, but it is much more difficult to find a relevant use for them or apply them in a way that is immediately profitable.
On-demand innovation, design, or creativity is more likely to happen when thought and direction is given by company leadership on what to do with new ideas. People need to know that it is ok to think differently than others or even counter to what an organization may be doing, particularly if it involves developing a new solution. Employees also need a venue or forum in which to share the idea and then a process to turn it into reality.
When people get in the habit of thinking creatively, the ideas will tend to flow more frequently and seemingly at will. Just as you would train your body to run faster by doing specific workouts on a track, one can train their mind to open up more quickly to encourage free-thinking and higher levels of conceptual thought.
Over time you get used operating at this rate and, whether you are running faster or generating more ideas, it tends to come more naturally. In time you might get tagged as someone who always had good ideas, but the reality is that it is something that most people can pick up, but you just have to put in the time to practice your craft.
What do I do? I read quite a bit and I make a point to write everyday. This has enabled me to talk conversationally about a wide range of subjects which also helps with generating ideas for this blog. The writing forces me to come up with 200-400 words daily that offers a different perspective than what people are used to seeing.
Innovation can happen on demand, but you have to figure out what exactly works for you and your organization to stimulate it.