Once upon a time, I was a law school graduate. I'd gone to a law school ranked in the top 20 in the nation, self-studied, and passed the Bar straight away. Then I entered the world of unemployment (well, technically, I had a job at Sears selling electronics). All this was because of a *ahem* "misunderstanding" with the firm I clerked for between my second and third year of law school which led to my not doing a serious job search until it was far too late in my 3d year of law school. The post Bar passage job search went appallingly poorly. Finally, after an interview in which a public defender's office basically told me they weren't going to hire me because I was overqualified and would leave as soon as I found a better job, I decided to start practicing on my own. Thus began my life as a criminal lawyer.
Scott has offered two models of how to become a solo criminal practitioner. I took neither of these paths and I thought I'd offer a guideline from experience on how it can be done.
The Hard Work / Frugality Model
Rule #1: Keep your costs down. As you begin a solo crimlaw practice you need to keep your costs to a minimum.
I started out with three Sears' suits, a computer, printer, dial-up internet, subscription to VersusLaw (along with the free use of FindLaw and All Law), a folding table, folding chair, cardboard file boxes, one phone line, fax/answering machine, and business cards. This was all set up in the living room of my POS apartment.
I took the steps necessary to get onto several local court appointment lists. Meanwhile, I spent a lot of time at the courthouses, watching what happened in the courtrooms - not just the interesting trials, but also arraignments, sentencing hearings, bond hearings, etc. so that I got a feel for what actually happens. Once clients started being assigned I met them at the courthouses (every courthouse seemed to have someplace I could do this). In fact, I would send letters out to clients setting exact times on Friday afternoons and sit in the law library and wait for them to come meet me. Since few clients actually showed, I spent time reading through practice books, learning about things particular to Virginia and developing the paperwork I'd use in my practice (read through the forms books to learn paperwork and jury instructions books to learn law). As there was no court on Friday afternoons, I also got to meet and talk with a lot of the people who worked at the court (clerks, deputies, the prosecutors' support staff, etc.) who were important people to know as my practice developed. I also made a point of getting to know several of the attorneys who practiced frequently in the courthouses. I didn't develop any "hard" relationships with any of them or get a mentor, but had a group of people I could ask questions about difficulties I was having. In fact, not having a single person to turn to probably helped because I (to the best of my knowledge) didn't wear out my welcome with anybody by being too needy.
You'll notice that, except for the business cards, I didn't put any money into advertising. You shouldn't either. For the small practitioner, with very limited funds to spend, advertising is a black hole which either does not produce results or produces results not worth the money spent. If you feel you must do something, join legal organizations: Bar committees (young lawyers), ethnic based Bars, practice area Bars, Inns of Court, etc. These are more likely to pay off with both referrals from people you meet and build your local reputation/influence.
Work hard, work smart, be frugal, and you can get there. Don't expect it to be fun though. I grew out of my apartment to a room rented in another attorneys office, to my very own office with nice furniture and everything. I got - and kept - the legal side under control. Coulda used a partner who had been to business school for things outside of the legal arena, but that's something you might want to ask Scott or Mark.