There are no one-size-fits-all "best" settings.
Pretty much this, but generally you want to shoot at around the optimum aperture setting for the lens. On my
M2P this seems to be somewhere around f/4, with anything beyond f/5.6 starting to show noticeable softening of the image. For maximum average sharpness across the scene you want to be focussed around 1/3 of the way into the scene, but if you have a specific point of interest - a building or whatever - then just focus on that. If in doubt, take a few exposures with different settings.
Keep ISO as low as possible to reduce noise, but you'll need to balance this against light levels and how stable the drone is; if it's getting buffeted by gusts of wind, then you may need to increase this to keep your shutter time down. Likewise, in lower light levels around sunrise and sunset you may need to increase it in order to keep the aperture closer to the sweet spot.
Since for stills you want the drone to be static, then using "Tripod mode" (if available) will make fine tuning composition a little easier and make the drone work a little harder at keeping still when hovering.
I'd recommend shooting in Raw+JPEG if possible; you'll get a lot more DR out of Raw files, but if the JPEG is good enough that'll save you some processing time. Ultimately, images from drones (Raw or JPEG) are no different from any other camera, so any decent post-processing guide you can find via Google will do.
Andy