1. Expect to re-write your code and do not over architecture.
2. Use consistency and agree upon the rules.
3. Solve system problems, not the immediate problem.
4. Keep sprints short and features small.
5. Focus on good database design.
6. Avoid processes that add too much overhead.
7. Document your code using 2 styles - self documenting or inline documentation
8. Build microservices over large monethletic codebase

Source: https://medium.com/helium-mvc/programming-principles-for-early-stage-startups-1215ad14bcb8