1. Innovation (often) comes from constraint (If you’ve got very few resources, you’re forced to be very creative in using and reusing them.)
This deserves to be #1 on the list. We are always given a limited amount of resources, and in our case, perhaps most limited of all is time. Every second counts and we must use it to the fullest.
2. Don’t fight culture (If people cook by stirring their stews, they’re not going to use a solar oven, no matter what you do to market it. Make them a better stove instead.)
Very true. Not all people will be open to your ideas, so being creative in solving your ideas (piggy-backing off of #1) is essential. Culture is what holds us together as a species, so pulling it apart would devastate us (after all, we Americans like our cheeseburgers).
3. Embrace market mechanisms (Giving stuff away rarely works as well as selling it.)
If it ain't broke don't fix it! We can't afford to lose any resources, much less time!
4. Innovate on existing platforms (We’ve got bicycles and mobile phones in Africa, plus lots of metal to weld. Innovate using that stuff, rather than bringing in completely new tech.)
The example is perfect. Simply putting a small generator on their bicycles would generate tons of energy, lessening their need for fossil fuels. This would definitely help their financial state in the long run, not to mention the environment!
5. Problems are not always obvious from afar (You really have to live for a while in a society where no one has currency larger than a $1 bill to understand the importance of money via mobile phones.)
Step in someone else's shoes why don't you! This allows for you to UNDERSTAND the problem. You are completely unable to solve the problem if you don't know what it is!
6. What you have matters more than what you lack (If you’ve got a bicycle, consider what you can build based on that, rather than worrying about not having a car, a truck, a metal shop.)
If only, if only. This is not your fantasy! This is the real world! Things are far from perfect, so this relates back to the first one. Creativity is a must when developing solutions!