A timely topic. I'm working on this a lot lately so I can sing and play at the same time. For good mic technique, I just plain can't be looking down at my hands and the keys all the time.
The ideal would be playing with my eyes completely closed, but I'm taking baby steps in that direction. One is just keeping my head up and using peripheral vision more, with the occasional quick glance at the keys if I can do so without moving my mouth away from the mic.
Another is literally feeling my way around the keys, figuring out what my fingers are touching and how that can guide my movements. The black keys provide a particularly nice set of landmarks for that.
I'm also working on sight-reading a bit more, keeping my eyes on the music, similar to my mic practice above.
I'm also finding that when I don't know a piece very well, I'm trying to imagine the keys in my mind's eye and let that guide me. However, when I know a piece really well, I stop doing that and just hear the music, and somehow that guides me even better than trying to reduce the movements to something visible.
Great topic, and looking forward to hearing everyone's thoughts!