I am a professor, I have been on more than 20 doctoral committees.
Most of the answers here are focused on, or call attention to picking a topic. IMHO - by itself this is not a good strategy.
In my experience, all dissertation decisions hang on one thing: the candidate's ability to understand how gatekeeping works. That is to say the classic error is the doc candidate who thinks they want their work to be great so they find the smartest people on campus to be on their committee. Translation: the four biggest egos in that discipline on campus are now on your committee. Good luck with that. Applying such a belief system (get the best and brightest) has the potential to inspire Intra-committee disagreements. That's risky. The worse-case output is the dissertation never gets done and it's not the candidate's fault.
IMHO if you want to create the most favorable conditions for graduating, research your potential committee chairs. 1) are they well-liked, respected? 2) research potential chair's doctoral committee history and records of how many successful/not successful dissertations 3) information interview your potential chair. 4) once chosen, ask your committee chair who should be on the committee.
The chair will likely recommend people who are agreeable with their ideas. Your committee meetings will be friendly. Don't get me wrong, you still have to find a good topic, be clever, and write well. A good advisor will steer you away from rough seas, heal weaknesses in your work, or advise strategies to keep your work relevant. IF you don't have that in your corner, you can still finish, it's just a lot more work to figure that stuff out on your own.
IMHO when it comes to topic and writing, buy or otherwise acquire a doctoral candidate or 'dissertation' handbook. Most universities have them in some form, usually found at the department level. Get one, read it, follow the guidelines laid out by your department -- and keep a journal of your committee meetings. Where you can, use the rules (and your notes) to your advantage.
The bottom line is that earning a phd requires you to pass through an institutionalized system. Such systems have rules and structures that can be learned and used to create pathways to success.
My experience on doctoral committees -- 20% of the dissertation ideas are not (and never will be) well conceived, 20% are exciting and interesting, The middle 60% are well-written -- or technically well-executed (and not so well-written), but otherwise good. Prolly 10% of candidates are rejected, and we always attempt to counsel our candidates to bail out early if we think they won't make it.
Good luck with your ambition. It's worth the effort. I was 20 years owner of a software company, now 20 years as professor.