G: TL;DR: The old Xbox 360 Kinect generally works best centered with the TV, slightly above eye level, angled slightly downward, with you standing about 6–8 feet away. The biggest real-world improvement people report is mounting it higher rather than lower.

Here’s the distilled version from Microsoft guidance plus long-term user experience reports:

• Mount height: about 2–6 feet off the floor, but closer to the upper end tends to work better. citeturn0search2turn0search6turn0search25
• Best practical position:
  • Top of the TV is usually preferred over below the TV.
  • Ideally within about 6 inches above the TV. citeturn0search6turn0search25turn0search9
• Distance from player:
  • Sweet spot is usually 6–8 feet for full-body games.
  • Absolute minimum is around 4–5 feet, but tracking degrades. citeturn0search9turn0search13turn0search17turn0search28
• Angle:
  • Slight downward tilt is ideal.
  • Don’t manually crank it upward; the Kinect was designed to look slightly downward at the play area/floor. citeturn0search9turn0search28turn0search25
• Floor visibility matters:
  • Kinect uses the floor plane as a tracking reference.
  • Coffee tables, blankets, clutter, pets, or chairs between you and the sensor can genuinely screw with tracking. citeturn0search9
• Lighting:
  • Avoid direct sunlight or reflective IR sources.
  • Windows behind you can reduce accuracy. citeturn0search2turn0search25

The “ideal” old-school Kinect setup most enthusiasts eventually converged on looked roughly like this:

        [ Kinect ]
      ----------------  top of TV
           TV

        (6–8 feet)

          You

Or even better:

Kinect mounted slightly ABOVE TV height
looking downward ~5–10°

A weird but consistent finding from user reports:

• Raising the Kinect higher often improves tracking in smaller rooms because it can “see” your limbs without furniture occlusion. citeturn0search6turn0search13turn0search28
• Low-mounted Kinect setups tend to lose feet/knees more often.

If you want the closest thing to a “golden setup” for the original Xbox 360 Kinect:

• Kinect centered horizontally with TV
• Lens around 5–6 feet high
• Slight downward angle
• Player at ~7 feet
• Clear floor
• No sunlight blasting the room

That was basically the configuration people ended up rediscovering after years of fighting with Dance Central and Kinect Sports.