I'd like to do something great for a change. How do I begin?

I'm a designer, and I've been living a placid little life as a design lecturer for the past few years.
I guess I just realized that this bores me.
I'd like to get back into designing for industry, developing innovative things, or write a great book, or start a project that really shakes a few walls.
But I've learned one thing during my quiet years:
Great stuff needs great preparation.
What should be my first step?

I think you should start by knowing what you want to do. "something great" doesn't count as a project description, I'm afraid. Find a problem that gets to a lot of people and solve it, so you can be sure to develop something useful.

Start by doing a simple thing extraordinarily well.

Try to find something that the industry really needs but that isn't offered from any company.

Some industry types are really weak because hardly gears are offered for plants of that type.
One of these weak industries is the foundry industry for example.
I've already realized some gears for that industry which are better than those of big companies.
Their products are more side products than products of "companies main interest".

You want a product that shakes some walls?
Try to beat some of the big companies with little budget.
Be better than their old but sometimes really complex systems.
If you can manage this, belive me, some walls will start shaking.

Dream and focus on what you really like.Also, I recommend checking out www.learntosucceed.biz. They can make the difference, sound career advice and they will answer your specific questions.
Good Luck.