It takes practice. A lot of practice and a few stinkers here and there to "educate" oneself. Despite other's advice I've, uh... tried various approaches and experiments and pretty much have figured out what works and what doesn't. Had to learn the hard way.
It does help to have a Carbonator cap. That way one can carb up a sample to see what it will actually taste like carbonated. I may be in a minority in this but have spigots installed in all my fermenters. This gives me the ability to draw off samples whenever I like, which is particularly useful when trying new yeast, temperatures and recipes. Again, once I've establish how things will behave I won't fiddle with the beer and leave it to do it's thang.
And quite certainly the brewer can have their beer ready to be drunk in less than a week. Just takes skill, knowledge and the right approach and criteria.