The answers come with asking, waiting, and trying but still what makes a good PSU? It isn't easy to find a "good" one without knowing a little about the types, materials, and basic features involved. The best way to look for a PSU is to know your system, connections are most important since the wrong ones lead to needing adapters, splitters or not even working with the system. Wattage is another big point to think on, whether it is an old system or a new build, too much wattage wastes money and too little can't run the system properly. The last main point to think about when choosing a PSU is cooling, remember that a PSU pulls double duty as a case exhaust while still needing to cool itself for stability.