Best ways to recognize if friendly or enemy aircraft

[F16_Neo]

At dot distance: Location, behaviour.
At LOD range: Shape, color.
Closeup: Markings and features.

Sometimes I still find myself aborting chases when I get to step 3. And yes, FF still happens, even if very rarely nowadays.

Online you should take great care, all pilots don't take FF as lightly as I do I've learned...