The first thing is to recognize that different players have different preferences. There are some players who like to jump in as quickly as possible and learn the rules as they go. There are some who can’t even make the first move without knowing all the rules. Most people are somewhere in between, but I like to ask the players what their preferences are.
Especially for complex games, I like to set the tone and expectations of the first game by saying, “This is a learning game.” If I remember, I give the option of “We can play a couple of rounds to get a feel for the game and then decide if we want to start over.”
When I teach, I will point out things to the newbies as the game progresses. For example, in Terraforming Mars, I will remind them about Milestones and Awards. I don’t like playing open-handed, but I will answer any and all questions they might have about what a card means or offer suggestions if they ask for strategic help.
I might skip some of the details about the end of the game and save it for when it is getting close. Again with Terraforming Mars, I won’t explain the “And once the last generation is triggered, we’ll play out everyone’s actions, then do production, and then you’ll have one last chance to build greenery tiles from plants,” until I think the game is in its penultimate generation.
I highly recommend that you only have 1 teacher. It can get really confusing if multiple people are trying to convey information. A little supplemental input from others is fine or even welcome, but when I’m teaching, let me teach, and if I’m learning, let me focus on one voice.