So you just got a brand new pair of
Behringer,
KRK, or
Event active
monitors. Or if you're one of the lucky few with deep pockets, maybe you got a
Yamaha,
Mackie or Genelec active monitors. Nice!
So how do you place your new monitor on your desk for proper monitoring of your music?

The rule of thumb is imagine an equilateral triangle where the tips of the triangles touch the left and right monitors, and your head. The distance between the left and right monitors, and the distance between the monitors and your head (i.e. where you're sitting, i.e. the SWEET SPOT) should be approximately equal. Now, point the monitors inward so the tweeters (or high-frequency drivers) approximately hit your ears, i.e. at ear level. At this point, you may do some fidgetting if you want it more toed-in or less. But this is a good starting point when placing your monitors.
This assumes that your head and monitors are on the same plane/height. If your monitors are placed higher than your head, tilt it down so the tweeter's line of fire is approximately hitting your ears. We're not too worried about the woofers or low frequency drivers since they won't be as directional as the high frequency drivers.
What can you use to tilt the monitors down?

You can use these
Isolation pads. They're also good since they decouple (or isolate) the base of your monitors from your desk. That way, you don't get symphatetic vibrations (especially of the low frequencies) which results in unclear stereo imaging. Also, sometimes when a monitor is sitting directly on your desk, you can feel the whole desk vibrating due to mechanical vibrations of the monitor being transferred to the desk. These pads reduce those vibrations too. For less than $40, these pads are a great addition for your studio.