I wanted to give back to the community now that my MBA admissions journey is over. I've left some facts and thoughts below, would by more than happy to provide additional insights if it would be helpful.
Undergrad: Large state school
Work experience: Manager at a Big 4 firm
Admitted to: Columbia, Kellogg, Yale, NYU, Darden, and Duke
I'd start with saying, never sell yourself short. I'm happy with my results but I can't tell you how many times people thought the two M7s and Yale on the above list just weren't going to happen (and anything beyond that was near impossible). Be honest with yourself and realistic, but don't be afraid to throw some Hail Mary's. If you are a strong applicant that can present well, go for the best. I would have thrown apps to H/S/W if I could do it over again. Don't have any regrets.
I agonized over my quant score on the GMAT (<Q48), and was concerned I would be dinged on that basis. I'm proof that is simply not the case. Put great care into your application and don't worry too much about having a non 50/51 score, presuming you are at least around 45+.
Coming from Big 4 and a state school, its easy to think that if you don't come from a top undergrad with BB IB or MBB experience that you are going to lose out to those folks. Similar to the GMAT point above, that is simply not necessarily the case. A capable person is a capable person, regardless of work or undergrad pedigree. Let that shine through your essays, resume, and interview. Adcoms are people too, remember that and craft a compelling story. I was told on multiple admissions calls that my essays really pulled them in and made an impact, take your time on those.
From a timeline perspective, I wrapped up the GMAT this past October after about 2 months of studying, and then knocked out all applications between November and early January. The only way I was able to do this was by taking a ton of vacation. If you have a demanding job, I don't recommend you apply to as many schools as I did, at least not in the same round. Another thing that was tough for me was the interviews from a timing standpoint. In February I felt like I was getting on a flight (or multiple) every week to fly to a school to interview. Make sure you have the support at work, otherwise this can get difficult to manage. In short, split up your applications among rounds 1/2.
Please let me know if there is anything else I can share if it would be helpful to you. Best of luck!!