The best advice, in all seriousness, is to stop thinking about it.
If you are in doubt, salute. I‘ve never gotten in trouble for saluting "when I shouldn‘t." On the other hand, I have been corrected for not saluting, though that hasn‘t happened in many years.
If anyone is really oh so concerned that "gee, I don‘t want to look stupid", you may as well give up on a career in the Forces right now. Your first years are all about paying dues and learning things the hard way at times.
Salute often, salute with pride, and don‘t be too chicken to salute because it makes you feel uncomfortable. Paying respect isn‘t something we‘re supposed to be afraid of.
And when you walk past the National Flag flying outside the building you work in, salute that too - every time.
Salute the flag outside of Wendy‘s when you stop for a hamburger on the way to parade.
Okay, don‘t salute the flag on the back of that **** ‘s Angel, but you get the idea.
I can‘t imagine anyone getting in too much trouble for having "too much respect."
And once you‘ve been in longer than ten minutes, you will start to get an appreciation for where and when to salute; as pointed out, every station or base is a bit different.