To reiterate your first item, a DO I would suggest is DO pick a partner that can make sales and close deals. The purpose of any business is to drive revenue, so how come so few new tech entrepreneurs focus on this from the very beginning? Why do sales people get such a bad rap? They are the only people in your organization who (if done right) don't cost you money. Dev, product, marketing... they are all cost centers. Sure, product design and development is important, so is marketing and related activities, but if no one is dedicated to actively selling and crucially, closing deals, nothing else really matters (because you're out of business, literally). Moreover, an experienced and dedicated sales-focused co-founder will provide you with more actionable and relevant product feedback (i.e. direct from potential customers) than anyone else.
The old saying, mo' money mo' problems, doesn't exist in business.
As our relationships evolved we learned to read each other better but it took time to get to that point.
