By working with people who know how to do it, and learning from them.

There aren't many shortcuts one can take in that area -- the big difference between junior and senior developers is that the senior developers have experienced what can go wrong, often learning from their own mistakes and the mistakes of their employers, so they are better able to make design/architecture decisions.

If you're a junior developer and you don't have good senior people to learn from in your job, it's time to start looking for another job.