Tips for playing on-stage?

I asked a similar question here a couple months ago, asking for tips for playing with a live band. You folks helped me out a lot, so I figured I'd ask some advice again, this time about playing in live venues. (Same band, we're doing pretty good so far 😁)

I don't own a keyboard amp yet, so I almost always run into FoH. (I've run into a guitar amp once or twice in really small spots. Didn't sound great.) I've got a fully stereo setup that I'm finding is a pain to make mono when circumstances demand it. And hearing myself out of the stage monitors has almost always been a pain. The different presets on my synth don't sound too dynamically different on their own, but on-stage it's suddenly night and day whether I'll hear what I'm playing. On very small stages with no monitors to spare, I've just been SOL a few times and just had to hope I was sounding right.

All that rambling considered, have any of you live synth vets got any tips or insights for a newbie, related to these issues or otherwise?