The menu is pretty simple on this, but is there a list posted of preferred settings? I've been wading thru the pages and can't seem to find one.
There's a setting for mono vs stereo. The nomenclature can be confusing. Mono doesn't combine both inputs to save to a single recording. Mono still records each track into independent files, so you can recreate a stereo mix later. (It's easy enough to split a stereo track or join two mono tracks in your DAW, but my current preference is two mono tracks.) I think it changes the playback in your headphones, so it's not totally useless. Test record both, load the output of both into a DAW, find your own preference. I prefer recording in stereo and do exactly this with the F3 set to mono.
A lot of mics step down phantom voltage, so you could try +24 if you use a condensor and check if the noise floor doesn't change. This might extend battery life a little. If I have USB power, I just run it at 48 because it's the spec.
I turn off the backlight so it doesn't annoy others or draw attention while recording.
Line level becomes important if you connect to a camera. I've always just saved to SD card and merged video with audio later.
If pre-record is at all important to you (a band starts playing without warning after a break, as some are known to do) having 3 extra seconds by keeping the sampling rate at 48 kHz gives you more time to capture the full intro. I keep it at 96 unless I need more recording time. It can't hurt but might help.

I keep "remaining time", since it's more valuable to know how much time is left on the storage than to know how long ago Record was pressed. (The other might be more useful if you heard something cool and want to jump to it right away so you look at the time when that cool thing happened. It's certainly a preference thing...)
32-float for sure.
I leave it on PC/mac even when connecting to a smartphone because my phone provides enough current to run the F3 via USB.
So, my current settings as a list:
- Recording: Filename "date", sample rate "96", format "mono", prerecord "on", sound marker "off", counter "remaining time"
- Output: HP alert "-20", line "+4, limiter off no delay"
- USB I/F: PC, linear (works more generally with Linux), loopback "off", mono mix "on" (I use a single-ear headphone while recording instrument rehearsals), monitor "on"
- System: date "YYMMDD" (better for sorting), LCD "off, contrast 3", power "Lithium, 10 minute auto-off", timecode (dunno, not a professional video guy)
- Source: "MIC Phantom, 24V", HPF "off", invert "off", delay "0"
- Etc: waveform usually between 1 and 8 but it doesn't matter except during in-device monitoring/playback, HP usually 70 to 80 (lower when direct into IEMs), always on HOLD unless otherwise necessary
On the HPF point, use your judgment. Generally, off is preferred for live music.