For those that don't know. It's pretty simple.
Go to your TV's settings, then go to Picture Mode - you'll see choices like, Standard, Dynamic, Movie, Sports, ---> [GAME] <----
And then choose Game. What this does is turn off all bullshit post processing the TV does to minimize input lag. Also, most video-philes agree that these extra things, not only add input lag, but fuck up the natural image as well.
You can also adjust sharpness and color and all that stuff to your desire afterwards too. Setting your TV on game mode often turns the sharpness and color way too high. You can adjust those settings down and everything should be good.
DMC5 is the only game that I've played, where there is a one time message (and only one time, so it's not invasive) where it recommends the player to put their display to Game Picture Mode.
I wish other developers did that too. You can't blame people if they simply don't know. So education on these things is important. I mean, thank the person who told me about it, all those years ago.