Entrepreneurs preparing to hire their first employees should proceed with caution. It’s costly to commit to an employee’s salary and benefits. And what start-up can afford to have even one employee who isn’t working to full capacity? Firing an employee can mean not only severance pay (and sometimes litigation) but also time and resources devoted to finding a replacement. The first questions start-ups typically wrestle with are whom to hire, when and where to find good candidates. The following is a rundown of some basics.