I've been playing a lot out of open G for a while, and have found that the biggest thing is finding the movable chord shapes. The two shapes I use variations of, by and large, are the G shape (so barring all the way across, but you can make it a minor chord by dropping the second string, which is the third of the chord, one fret to make it a minor chord, or fretting the top string three frets above the barre to make a 7 chord) and the C shape, which is movable if you barre behind it. With those two, you can work out most of what you need. I found it much easier to internalize this when playing songs, not just trying to memorize the chord shapes, but you may well be on top of that.
Here is the chart for open G like was referenced above, but I'd try less to memorize this chart and more to think about the base chord shapes you can use and adjust all over the neck.
Another aha moment for me was this video, which laid out a thing I'd noticed, that Ry Cooder often plays open G tuning when playing songs in the key of D, which is a lot of fun: