Through layoffs last year I was pushed into solo practice even though I had been contemplating it for a couple of years. While the last year has been challenging, it has ultimately been very rewarding. I can't imagine working under anyone else ever again. Plus, the more I work the more I am rewarded and not "the firm."
To your questions:
Running a patent practice is, in almost every way, just like running any other business. The same challenges apply to every entrepreneur. The balance between creating work product for existing clients, networking to keep the pipeline full, conducting administrative duties, along with client relations is the game. Unlike working at a firm, where most of the time associates/non-partners are shielded from clients, you must learn to develop your client maintenance skill set. This can also be the most time consuming part of the business if you are unwilling to set boundaries for clients.
Here are some ideas:
1. Learn to manage your time effectively. The 80/20 principle is alive and well; look for ways to implement it. Buy "The Four Hour Work Week" book and use his ideas for managing clients, email, and phone calls. Also, Frank Sanitate has some great stuff on how to manage your practice efficiently. Consider an a$$hole tax for perpetually difficult clients.
2. Focus on developing a good balance between efficiency and quality. (Read into that what you will)
3. Learn to sell. Everything about running a solo shop involves sales. (Yes, even a law firm) Learn to effectively sell your services and your ideas to people.
4. Learn to be a good administrator (docketing, letter writing, etc.) on your own before you hire an assistant. Until you can do every job in your office blindfolded, don't delegate that to someone else. Once you do hire help, learn to efficiently delegate tasks.
Lastly, some personalities aren't equipped to run a solo business. If you are not outgoing or prepared to develop a thick skin, this isn't for you.