Field Guide or “How-To” For UFOs at Night?

Does anyone have a link, or know where to find a guide, or even just care to share here, the following:

How can you tell if lights at night are UFOs or even unusual?

I frequent http://reddit.com/r/askastronomy and pretty regularly people ask about strange lights at night (which are often either planes, planets, or increasingly a string of Starlink satellites).

While I do know a bit of the astronomy angle, I know little (as in almost none) of the satellites or airplanes angle. So, on some level, I see UFOs all the time!!

Are there some rule of thumbs? Like:

“only white, yellow, and red lights are used in aviation” (so orange or green would be remarkable)
lights never come in a line of 3 etc.

I love looking at the night sky, and see weird stuff all the time, but I don’t know enough to know just how weird, I guess…