I've been going on about getting the right people: partners, advisers, and first employees. But how do you actually figure out who the right people are? This is the most important thing a founder does in a company. The key principle is to be very demanding and deliberate in the hiring process.
Cast a quality net: Be intelligent about posting locations. If you post on craigslist, you are guaranteed to have applicants that can use a web browser. Posting on your own website's careers page gets candidates that are interested specifically in your company.
Present your company honestly: The best candidates are evaluating your business at the same time you are evaluating them. Make sure to have a clear description of the job and the nature of the engagement the candidate will have at work. Be prepared to show revenue projections and talk about the health of the business.
Setup Brutal Filters: Be objective about what qualities you want and don't want. Send an email interview that requires some work to respond to. Give preference to candidates that care about presentation of their answers. Consistent typography in email responses is a good sign of attention to detail and pride in work product. Be slow to respond to emails. Give preference to candidates with enough initiative to follow up.
3 or 4 interviews: Email, Phone, 1 or 2 office interviews. Make sure the candidates are really committed to getting the job.
Ask for 10 references: If the candidate can't find 10 people to vouch for them, its a bad sign. If they don't feel like putting in the work to dig up the contact info, its a death knell. Don't hire people who won't work for what they want.
Admit mistakes quickly: In the unfortunate situation where you've picked an inappropriate candidate, its best to go your separate ways quickly. Don't drag it out. This represents a failure of your job as an employer, not a failure on the employee's part. Any time you need to let somebody go, you should be outrageously mad at yourself for letting the situation happen.