When at the earliest stage of starting your company the following lessons i have learned:
1. Select co-founders that compliment your skill-set, not overlap
2. Focus on the monetization strategy early
3. Iterate often - plan, build, validate, re-plan, build, validate ...
4. Identify all your stakeholders early. ALL of them. Then go about answering the value you add to each one. If conflicting, work through that until you find the sweet spot.
Get to work! :-) -d