First decide whether you are truly cut out for practice ownership. Running a small business as an added responsibility to being a full-time clinician is not suited to everyone. Then seek all the prevailing advice about how to start-up a practice (there is a ton of it out there in forums and elsewhere), and whether buying a practice or starting up is a better choice. There are certain nuances to ophthalmology practice but much of the start-up advice pertaining to other medical specialties and allied health fields will also be helpful.
As far as consultants go, it's like anything else, there are good and bad ones.