Akins' Laws of Spacecraft Design...

Here's a list of design principles that will ring true to any experienced engineer, in any field.  Here are a few that are just as applicable to software design as they are to spacecraft design:

Design is an iterative process. The necessary number of iterations is one more than the number you have currently done. This is true at any point in time.

Not having all the information you need is never a satisfactory excuse for not starting the analysis.

There is never a single right solution. There are always multiple wrong ones, though.

Don't do nuthin' dumb.

Schedules only move in one direction.

A designer knows that he has achieved perfection not when there is nothing left to add, but when there is nothing left to take away.