Finding the "tonic"
"The" moment is most often going to be the final chord. More often than not, a song ends at a moment of rest, where the music feels like it has arrived "home". The root of that chord will be the home bass for the mode.
"Highway to Hell", for example, ends on an A. (Hear, for example:
Given the notes listed in the question, that would suggest A Dorian. (It's not — the song uses C# more than C, making it A Mixolydian — but Dorian would be the conclusion based on the information given in the question.)
Each diatonic mode has its notes and intervals that distinguish it from the others. So to get the sound of that mode, the music will tend to emphasize its unique features.
We know "Highway to Hell" is not Lydian, for example, because it doesn't call attention to the #4 Lydian has relative to major. It's not Phrygian, because it doesn't make use of the b2.
The problem of modes and popular music
"Highway to Hell" is in A Major; however, it avoids G# in favor of G. This is a characteristic quirk of rock. When the song goes to the V chord, it uses the leading tone rather than the lowered seventh of mixolydian. That consistent presence of the leading tone is what makes the song major despite the frequent use of the b7.
One common place for the b7 to appear is in the VII chord itself. This is often used to move to the I chord (the "backdoor cadence"). A song that uses this progression and avoids the V chord with the leading tone (i.e. avoids the chord altogether or uses the minor V) could be more properly said to be in Mixolydian.