I beleive that there is one answer to this question which does 80% of the job, it is easy to express and yet in the same time impossible to grasp for so many programmers/managers which leads to so many awful codebase.
As the post says very well: start by thinking about what you would do if you had infinite resources. That's the ideal case. Find a real bottleneck (money, cpu, memory, ?) and rethink your architecture accordingly, find the next real bottleneck and so on.