1, Play the least-threatening killer you have, nothing with exposed or chainsaws. No Legion/Knight/Nurse/Billy/Bubba/Artist/Trapper/Pig/Plague/Nemesis/Wesker/PH (either of them). No one with teleports or insta-kills either. Survivors will instantly quit against certain killers, or lecture you in post-game chat. If you need help selecting a killer that survivors will like, I recommend looking up a current killer tier-list, and just choosing any killer in the lowest tier. Freddy or Clown are usually survivor-approved, but that may be subject to change.

2, at the start of the match, break every door you can find in the level. This allows survivors to start the game in a pressure-free atmosphere, and they'll probably complete a gen while you're breaking doors. Some survivors rage and/or quit if you find them at the very start of the game, so the solution is basically to find no one.

3, throw out quick hits at survivors any time you can easily connect, but don't down them. Also, the hits need to be obtained in a simple way...no mind games, or skilled use of a killer power. Some survivors will quit the second they see they're up against a killer that they perceive as being more skilled than them.

4, Always drop chase immediately after landing a hit, so the survivor can go heal. Anything more risks being called a "tunneler."

5, break pallets as soon as they're dropped; use no perks to help. Survivors like to see killers forced into doing things that are unfun, which means they want you to take the time to break every single pallet they drop. If they want to stun you, let them.

6, patrol a specific route, focusing mainly on kicking gens; kick one, then go to the next. The idea is to never have any one generator that is more pressured than the others; deviating from this may result in accusations of targeting certain players for their prestige level, streaming channel, etc.

7, If healthy survivors are repairing in a group, you are only authorized to hit each of them once. Always remember that you are not allowed to down anyone, unless a survivor gives explicit permission by pointing at a hook, then pointing at you.

8, if survivors are all injured, just walk around the map and try to break things until a survivor heals.
When people have healed up, the cycle starts again. If they aren't healing quickly, you may want to go hide in a corner of the map for a while, so they don't feel pressured.

9, when the gate is powered, just go open it. It gives you points, and the end-game collapse timer acts as a gentle reminder that the survivors must actually go through the exit at some point.

10, If you accidentally pick up a survivor, just stand still and let them wiggle free. Remember, you're not to down anyone. Getting a grab is just as bad as downing them.

CONCLUSION: In hundreds or thousands of matches, these are the methods I've discovered to make survivors happy. Survivors want the illusion of a threat and obstacle. Many don't LIKE challenge, they are happiest when they walk away with free points, pips, and achieves that they got with no chance of dying. Remember, the killer winning is the survivors having a bad time, and you'll do great.

UPDATE (26 April 2024)
11, The following is the official, survivor-approved build: meme addons (or no addons), with Distressing + Beast of Prey + Hex: Thrill of the Hunt + No 4th Perk. You must remember that a lot of survivors are very busy, just want to listen to music while they loop you, and they play the game with just the right amount of competitive spirit without trying "too hard"; using this build assures them you're in the game for fun, not wins.

12, Never nod at the survivors. It's rude, and survivors would never do something like that to you.

13, If a survivor is hiding in a bush or corner, it's very important to walk around randomly and pretend you don't know where they are before walking away. Survivors sometimes get tired of chases, and just want to alternate between doing generators and giggling in a clever hiding spot. Such things take REAL skill, unlike the gameplay of us killers.