For whatever reason, I don't exactly believe in free will or predestination. I generally subscribe to the theory that life is a giant "choose your own adventure" book: we have the free will to choose our path but each choice has a predetermined outcome. Now what does that have to do with a popular character leaving a popular mocumentary show? Well, there is a way for The Office to not only succeed, but also thrive once Steve Carell says his final goodbyes tonight. The show will just have to make the right choices after he leaves.
Focus on the ensemble.
Now, The Office has always been an ensemble show but each week generally revolved around Michael in some capacity. With Michael gone, the burden is dropped. The good news is there is already a strong group of characters there, ready to shoulder that burden. The bad news is there isn't a single character that could potentially take the reigns over the rest. The writers will have to make sure to distribute the stories around to all the various characters in order to survive and without promoting one character above the others.
Find Michael in other characters.
A lot of Michael's characteristics defined the tone of the show. He's awkward, sure, but his underlying desire to be loved was what permeated through everything he did. The writers will have to find that in other characters. Erin seems to have taken the naivety mantel and Dwight and Daryl have the corporate shenanigans covered. But a desire to be loved? Andy seems to have that in spades.
Explore Kevin, Erin, and the new cast members.
It seems that this year, they have been setting up the ensemble to share their burden once Michael is gone. Kevin has had an increased amount of screen time recently and should continue to do so. Erin has too. The Office has always grown their characters over several seasons (think Andy and Angela) so I see these two getting developed more attention in the next few episodes. Also we'll be getting two new cast members so getting to know them will undoubtedly take up some screen time. All of this goes along with focusing on the ensemble, but these four deserve a little more in depth analysis.
Avoid Jim & Pam, Creed, and Ryan
It's my belief that once Michael leaves, the other main focus of the show, namely Jim and Pam's relationship, should be removed from focus as well. It's not that it should be removed entirely, but they've reached their happy ever after, let them enjoy it. It would also be really easy to give more time to one of the fan favorites like Creed but Creed's strength as a weird character comes from only popping up once or twice an episode with something bizarre to say. Too much and he would lose his appeal. Ryan has the same problem. He's been given so much over the past seven years that he should be relegated to the background. Keep him as his current incarnation as a douche and let us openly despise him once or twice an episode.
Erin & Andy are the new Jim & Pam
While Erin and Andy have almost gone through their reservation of will they / won't they goodwill from the audience, they still have a season's worth of a relationship to explore. That should take care of the romantic underpinning that people have come to expect from the show. Besides, it's not like Angela and her Senator (State Senator) boyfriend have anywhere to go.
Don't worry about the new manager.
A lot has been written about who will replace Michael as the manager but you know what? Most of that worrying is for nothing. It doesn't matter who takes the position, what does matter is how the rest of the office deals with the new person. Take Dwight and Daryl. They're obviously invested in who gets it and if one gets it over the other there will be plenty of jealously and contempt to explore. And with all the hubbub of Carell leaving, we really haven't noticed that Rainn Wilson has expressed interest in departing as well. Not to mention that Dwight has become very unsatisfied with his treatment at the company. Now imagine that for a second. Dwight gone? Doesn't make who becomes manager seem all that important, does it?
So what's going to happen? Only the writers know. But it is possible for the show to go on and thrive. Whether they succeed or if the audience wants them to remains to be seen. But I trust the show and the talent behind it. They faced a huge uphill battle when they began the show and I think they can repeat the magic again.