Your Architecture needs to be "good enough". If you strive for the absolute best, most flexible, most extensible, blah blah, you will be stuck with analysis par

Your Architecture needs to be "good enough". If you strive for the absolute best, most flexible, most extensible, blah blah, you will be stuck with analysis paralysis and spend too much time upfront with less information to make decisions. Conversely if you just begin coding with no plan - you will have an unstable product that will fall apart at the first instance of some deviation from the normal. The (very hard) trick is to do a good enough job to deliver fairly quickly for a fairly stable product. Then be prepared to learn and refactor until it becomes better. How do you decide what is good enough? Experience...