I look at the body/canopy of the heli. In a stable hover, the heli will "hang" at a certain angle. Once you can recognize what this position is, that is your "neutral" position. This means that, with no wind, you can tip it forward to get some forward momentum, and then return to this neutral position to "coast" to a stationary hover. Recognizing this "neutral" or stationary hover position will keep you from over correcting when you're trying to hover. For example, if your start drifting right, you tilt back to the left to counter the drift. However, once you've stopped drifting right, you need to get back to the neutral hover position, or you'll start drifting left, now, and then have to tilt the heli right to counter it, and you'll keep going back & forth, over correcting each way.

This is a simplified view of things, since in real life there is always some wind (sometimes lots of wind and gusts), and you'll have to fight to keep it steady, but I've found that watching the body angle/position relative to this neutral position, as well watching which way it's moving is the best way to control it and minimize over correcting your controls.