Yes and no, it can be very straightforward or it could require some quick thinking on the spot.
I think it would be hard to find a textbook rescue in real life, there will always be a slight variation in real life. Sometimes when participating in a rescue or an assist, the solutions feel like they just present themselves to you. Other times you sit there after the fact, and wonder what you could have done better or differently to make the rescue go smoother.
Not all rescues involve a major event, just preventing or fixing small problems can avoid the whole situation of having to perform a life-saving rescue, so in that aspect you could say you rescued a diver from having to be rescued. You'll probably hear this or some version of it many times, "the best rescue is one that never has to happen".
I've had a few experiences where I have assisted another diver and probably prevented a situation a from deteriorating to the point of a rescue.
Recently in a pool session I was going over reg recovers with a few basic students. One was performing the over-the-shoulder reg recover and couldn't reach his hose. So I presented my octo in front of him, he chose to continue trying and didn't take it, so I waited for him to stop blowing bubbles before I gently pushed the octo into his mouth.
Another time on a boat dive, my buddy started to have a nose bleed on our safety stop. We were hanging on the anchor line when I motioned to her nose. She did a mask clear then signaled that she Wasn't OK. I asked her to signal what wasn't OK and she just flailed her arm once, from her head to her feet. Not understanding I tilted my thumb up then down to signal that it was her call whether we stay or ascend. She chose to thumb the rest of the safety stop. On the boat she told me that she wasn't feeling right, all over and had an equalization issue early in the dive.
Both situations were pretty straightforward. But there are other times when it's not quite so.
We have this local beach called Monastery that has notorious waves which will tumble you and spit you out covered in pebble sized pieces of sand. It's very hard to regain your footing if you do get tumbled, especially on scuba.
I was there with two instructors, several rescue divers, 3 other DMT's (I myself was a DMT), and 20 basic students; for a skin dive session. During our debrief (in street clothes) we watched one team get tumbled in the waves, one diver was being rescued by another while the third was waiting past the surf zone. We sat there and watched for quite some time. The assisting diver looked like he was in control, but he had trouble getting the other diver to climb up the beach slope to make an exit.
At one point our two instructors, along with 2 DMT's and a rescue diver, rushed out to assist. The entire class (around 30 people) would have followed had one of our DMT's not stopped them. When we got on site, half of us stopped to survey the waves that were coming in to break, the other half rushed right in and grabbed the diver in need of rescue. They immediately had to let go and backed off as a wave came crashing in. Three of us ended up pulling the diver out before the next wave crashed. Happy ending, we continued with a more serious debrief with the rest of the class. Even today though, we still talk about what we could have done differently.