Please note that it is the type/kind of work done, not the job title, that determines whether a position is overtime exempt. Calling a receptionist by a fancy title like Patient Reception Executive does not change the FLSA obligation.
The US Department of Labor decision tool at www.dol.gov/elaws/esa/flsa/overtime/menu.htm helps determine an employee's eligibility for overtime exemption and explains the common exemptions in more detail.
What if Hourly Employee Agrees to Be Paid on a Flat Salary for Simplicity's Sake?
While this would do away with a lot of painstaking record keeping, hourly employees cannot waive their hourly status, even if the employee and the company mutually agree on it in writing. Employees can sue their employers for back wages, and the employer can be fined for not keeping records of hours worked or not calculating overtime pay properly.
What About Employees Who Do Exempt and Nonexempt Work?
Some of this depends on what the employee's primary duty is, and for how long. Be aware, however, that exempt employees who do a nontrivial amount of nonexempt work in a given period may be entitled to overtime pay during that period. For example, if your receptionist (a nonexempt position) is on vacation for a week and your office manager (an exempt position) fills in, your office manager should be considered hourly for that week and should get overtime pay (if applicable).
What About My State's Laws?
Your state may have stricter laws about employee classification, hours worked, and the computation of overtime. Check your state's Department of Labor information at https://www.dol.gov/whd/state/state.htm.
When you are hiring staff, you need to consider what benefits you will offer your staff. Some options include health insurance, life insurance, dental insurance, tuition reimbursement, paid time off, and continuing medical education. You might consider checking with your colleagues in the area to see what they offer their employees to get an idea of what your potential staff might expect.