Hello,
What games are you going to be playing? I wouldn't touch any of the OSD settings, instead I would use your graphics card's control panel and increase the Digital Vibrance (NVIDIA) or Saturation (AMD). This will allow you to make out the difference between a player and the background in games such as Counter-Strike to name one. Other than that, just experiment to find out what you like the most. There are no right or wrong settings, it's preference. For best results you should calibrate it using a tool, as it can be quite hard to get the colors right, especially on a TN-LCD panel.
All the best!