Hook 'em and reel 'em in
So you can't just kill Survivors by hitting them repeatedly, although that is absolutely an excellent place to start. Hit them twice and they'll be downed, crawling on the ground, at which point you want to pick them up and place them on a hook. Hooks will be highlighted once the Survivor is picked up.
Place them on the hook, and the horrors will start picking them apart. They can be rescued very quickly by other survivors, so keep an eye out.
At this point, either hunt Survivors, or guard your hooked prey to lure in other Survivors, and ensure you kill the one you have. Killing just one Survivor early makes the rest of the game much easier.
Each Killer character has a variety of abilities, which are useful in different situations, and according to your playstyle.
For example, the default Killer, The Trapper, lays down traps to slow down Survivors and attack them while they're stuck. Good if you want to control the areas the Survivors can easily move through.
But that doesn't suit my playstyle. What suits me is The Hillybilly, whom you can also unlock early on. His Chainsaw attack charges up, and then speeds up and launches forward. Any Survivors in the way take big damage, making chasing them down much easier.
Finding the survivors
One of the biggest challenges will be finding where the Survivors are hiding. They could be anywhere. At first, they're likely to be on the other side of the map to you, so get moving.
After that, look out for explosion indicators, which will show you where Survivors are trying, and failing, to repair generators. Go there to scare them off the generators and hunt them down.
And as before, when a Survivor is hooked, consider staying nearby. It's very likely that another Survivor will show up and attempt to save them.
What's the status?
It will always help your game plan if you know the status of the Survivors your hunting, and luckily that information is always present in the top-left.
You can see if a Survivor is healthy, limping, downed, hooked, or dead. You can use this to keep track of whether Survivors can take one hit or two from your Killer.
If you decide to run off when a Survivor is hooked, use this to keep track of whether they are still hooked, or if another Survivor has interrupted