When I was going through things with the lady that wanted me to record the audiobook, she asked me to record a sample page from her book. I did and sent it to her. She asked if I could add effects to that audio quality, then gave me a sample of another narrator clip.
The main thing I noticed was that the narrator added a lot of EQ and compression. That makes your voice sound really crisp and come out more, and it helps a lot if you have a deep booming voice. In my personal opinion, I recommend that you don't use too much of it (it's fine if you add a little bit) for an audiobook. Even if you sound "epic," it's usually very distracting for a listener. But it's not always bad. In fact, it's very useful for online commercials, E-Learner videos, tutorials, intros, and sometimes character acting. The lady wanted it like that, so I added the effects, and she was satisfied.
This is the first sample without the effects:
The second sample with the effects: