I think Ramseytheii hit it on the head. When you're thinking of where the octaves are going and their final "resting place", they play almost by themselves. (This, of course, is for advanced pianists who can already play octaves.) Don't EVER overplay and ALWAYS relax after the passage has been played. But don't think of the each individual octave. think of where they're going and the final stop.
I think it is a bad idea to play fast octaves with 4th finger on black notes and 5th on white notes. I was taught that way but it failed the experimental test. I had been frustrated with speed and accuracy of the numerous fast 2-hands octave passages in the (quite difficult) Liszt Dante Sonata. When I changed to using ONLY the fifth finger (for both white and black notes), my speed and accuracy improved noticeably.It is relevant for you to know that I'm male, as males, unlike females, usually have their 4th finger LONGER than their 2nd finger (with finger #1 = thumb). So female pianists have shorter 4th fingers and may be more apt to use only the 5th finger in all cases, to enable a bigger span.
My remarks about preferring only 5th, not 4th, finger for fast octaves was intended for the situation where you are rapidly ascending or descending the keyboard. If you are only playing a few nearby octaves it is certainly faster to use fingers 4 & 5 (& sometimes 3) for the octaves.