Brewing the best beer possible requires the brewer to pay attention to each step during wort production and fermentation, and to execute each well. There are no “silver bullets” when it comes to making beer. In other words, there are no “do this one thing and your beer will turn out great every time” tricks to brewing — you need to do everything well to brew the best beer.
There are, however, practices that consistently lead to better homebrew, when all other things are held constant. I would argue the most important of these is raising enough yeast for an adequate pitch. For most homebrewers, this means making a yeast starter. As with most techniques in homebrewing, there are acceptable ways to make a yeast starter and the best ways.