Well the first thing you need to do is NOT post about killing someone because that's just evidence on you, if you actually kill someone the first thing the authorities will do once they find out is search for any data, so typically they'll check your phones, laptops, pcs.
You can kill them in anyway just make sure to wear gloves, clean blood stains with bleach because detectors have UV lights that can detect blood stains on the floor, walls, etc.
And if you burry the dead body make sure you burry it at least 8 foot deep in the ground and burry any dead animal like 4 foot above the dead body, that way when the dogs lead the authorities to the smell of the dead body they'll just think its a dead animal and go away.
Don't leave any evidence behind you and whatever you do, you have to die with the lie.
Don't tell anyone and even if you're confronted keep lying and claim that you DIDN'T do anything.
And try the organize the targets house in a way that would make detectives think they committed suicide just to push the thoughts away of you, good luck and don't do anything dumb.