I have found that the best way to stimulate your creative mind is to take a problem and try to solve it. And when looking for a solution, don't restrict yourself to technical areas that you are familiar with or to problems at work. It could be any problem that you see in day to day life.

Here's a list of steps which can help you start inventing:

1. Identify a problem. Find a problem that needs solving, or something that you think needs improving. This could be anything; it could be a social problem you see, an problem with a business, a problem in the kitchen... anything at all. Don't restrict yourself to areas where your expertise lies. For example, if you are software engineer, it doesn't mean that you should only try to solve software problems. Feel free to try solving problems in other areas like astronomy or areas like actuarial modeling. Sometimes the best inventions come from people are not familiar with a problem area, because they bring fresh insight to the problem.

2. Thoroughly understand the problem. Analyze the problem carefully and get to know it thoroughly. If it is a problem with some kitchen device, then get familiar with the tools used in the kitchen to understand how a cook works in the kitchen. If you are trying to solve a software problem, then you need to thoroughly understand the limits of the way things are done today. You will need a deep insight into the problem area in order to devise a practical solution. For example in the kitchen problem, whatever invention you come up with must be practical for cooks to use, and the only way to know this is to thoroughly understand the way a cook works.

3. Have a firm grasp of technology. You need to understand the fundamentals of different disciplines in order to create an invention. For example, if you are trying to solve a kitchen problem by inventing a new appliance, you'll need to understand the basics of engineering, mechanics, and the principles of machines. If you are trying to solve a software problem, you need to be familiar with issues of computational complexity, algorithms and so on.

4. Let your mind run free. Don't let yourself be restricted to looking for a specific solution. In some cases, this might mean not reading about other attempted solutions to the problem. You don't want to have preconceived notions of what cannot be done put into your subconscious. This also means letting you mind cross many different disciplines when looking for a solution. For example, it the kitchen problem, a solution might be a new applicance combined with a new working procedure for the cook and a new lighting fixture. Don't restrict yourself to looking at just a new appliance to solve the problem.

What not to do
I have found that the worst way to start inventing is to start with a blank slate, then start trying to invent something revolutionary. In other words, don't start thinking about inventing until you have a specific problem in mind to solve. Inventions are incremental improvements that improve our lives. Rarely do we find revolutionary leaps appearing out of thin air. If you really do have such visionary insight, then by all means go ahead. But for most people, inventing comes from finding a problem and solving it.