Humans
The thing that makes Fallout 4’s humans tricky is that they come in many different types. All humans are relatively easy to kill, being one of the only enemies that is generally susceptible to all different damage types. But, their ability to don things like power armor tends to give them an extra edge as well as some versatility.
Your basic and lightly armored humans can be taken out with any ballistic weapon, fire, or explosive. There is really no need to get fancy and waste your more powerful weaponry. If need be, you can hit them with some radiation from a gamma weapon. They are easily managed and those armed with guns would sooner go for cover than charge at you.
Melee enemies can be dealt with just like you would a Ghoul. Slow them down and you’re good to go. It’s the ones in heavy armor and Power Suits that you need to be wary of. Bring out your strongest weaponry, and if you have anything with armor piercing capabilities, use it. Energy weapons such as pulse grenades usually do a good job against these guys as well.