I am amazed at the number of my contemporaries who have decided to travel on the long road to a doctorate. In listening to my 'doctored' friends, it seems their many weird individual experiences are a normal part of the process. So here, in all humility, is a 12-step survival guide to starting and finishing that thesis, and getting the degree.
1 The 'original' idea Whatever your IQ, you need to be interested in one original idea deeply enough to sustain you. Do not compromise on this. A university ought to recognise your passion and accommodate it, as long as your subject matter is of scholarly value. If you are not interested in your subject, be it pink dolphins or yellow literature, you will not finish.
2 Family and friends Even with a brilliant idea, before you do anything, forewarn those nearest you. They need to be totally supportive of the time and money you are going to spend. Tell people it will take years; do not tell them you are going to do it in 18 months, because this almost never happens, even for full-time students.
3 The proposal Registration at a university will involve extensive form-filling and probably a 'research proposal' on what you are interested in doing and its inherent originality. There will be an interview, when academics from a department associated with your chosen subject will test your knowledge and depth of resolve. An alternative is to find a supervisor first.
By this whole initial process, you will learn the first contradiction in thesis writing: writing up the details of how you propose to do research before you actually do it.
4 The 'bronze moment' - acceptance You are now formally accepted on a course and your friends now know you are 'doing a doctorate'. You meet your supervisor, full of optimism about your intended work schedule and how soon you can complete ... Elation rules!