What preparation is essential to successfully transition to the civilian world?

I'll add to Vikki Nicometo solid advise that you do a baggage check of your attitudes and be prepared to take a humble pill if necessary. How you orient yourself to job seeking, being responsive to good counsel, and learning from the bumps like you had to learn as a MIL are good attributes. You see a lot of deep six the jargon, acronyms, and other things that are in your comfort zone. Transition by its nature isn't comfortable and needs to be managed. It also means in some or more ways, you need to change, but a better word is grow. Good luck on your journey.

Ranger Decker, looks like your at the top if your educational goals and possibly interested in security and defense matters. If you're considering getting out, start working on your IPBA, Intelligence Prep of the Business Area, for potential employers that you're interested in. Then start drilling down into potential neighborhoods or areas where you might consider establishing your base of operations.
Remember too, that the civilian world is different than the Army. Civilian supervisors and administrators are not necessarily leaders. They may or may not have large egos that get bruised easily. You may have to temper a direct and truthful military response so that it does not cause injury to someone with thin skin. That's been the hardest part of my transition. Best of luck to you in your transition.

Brilliant question! I’m going to answer this with a focus on just the parts I know – that is, finding civilian employment. I’m certain there are other parts related to family, military separation, etc. that others can give better advise on.
For finding civilian employment, these are the steps that I think are CRITICAL:
1) Get clear on what type of civilian career/job you WANT – not what you think you can GET, but what do you actually want to do? (There are resources to help you with this. A good coach is one. Feel free to message me for more info.)
2) Target VETERAN FRIENDLY employers who have those types of jobs. The reason I stress the veteran friendly part is that I understand that many employers don’t know enough about military experience to understand what you did. But veteran friendly employers usually have a dedicated team of recruiters to guide you and the hiring managers through the process. Many of those recruiters and hiring managers are also veterans.
3) Then start the tactical pieces – next up: the resume. Translate your military experience into civilian language. There are TONS of free resources out there to help you with this.
4) Network like your entire career depends on it – because it does!! Blindly sending resumes to online job postings is the WORST way to find a job.
5) Get some interview prep! From a pro! Not your friend, but someone who is an expert at interviewing.
I could go into salary negotiations, etc. but this is a good start.
If you want to ask questions, you can do so here or you can message me, or you can ask them live at the free transition teleconference I’m offering. If you’re interested in that, shoot me a message and I’ll send you the link to register.