'The [solo work] process starts very early on with the initial ideas of what the show is going to be about, who the voices will be, and how those voices come together thematically and rhythmically. So, rather than jumping in when the script is finished, it's very much a cycle -- the performer writing, my editing and suggesting, watching them improvising or reading more pages, workshopping it in front of an audience, then doing it all again.'-- Jo Bonney
In solo work, the playwright is the performer, usually presenting a number of characters in monologues relating to a shared theme. It's tough work, if you can get it.
Much of the power of solo work comes less from Structure when compared with conventional multi-character plays or even One-character plays -- though the audience still likes to know when it's time to go home. A key element in the success of this kind of work is how compelling you are as a performer.
The best way into solo work is to read solo performance scripts, then see this sort of thing in performance -- in the flesh -- or on video if you can't find the real thing in your local theatres.
A few scripts from some of the best of these solo
A writer-performer with one of the longest track-records in this solo performance business.
ORDER Bogosian's Talk Radio on video 
The only one of the solo crowd who draws characters and situations directly from real events and real people, capturing their Voice and actual words, but making it all work together as through a single author was creating it.
This is contemporary Docudrama at its best.
He's a master of the form and this is his masterpiece.
ORDER Gray's Swimming to Cambodia on videohttp://www.vcu.edu/arts/playwriting/