Start with the basics; document operational procedures, implement a change management system (can be as simple as an issue tracking spreadsheet) and hand them over to the new person for comment.
Start handing over the responsibilities that impact your time the most (As you are going to be training a new person, demands upon your time are going to go up for at least the first 2 months). This process will dictate the level of access you give them (but use common sense). Micromanage until you get a good feel for their abilities and work ethic, but be upfront with them about this. If they cannot handle a little micromanagement or are unable to explain why their purposed change is better when they identify something you did wrong, you do not want them as an employee. Other common sense measures include; Do not ever let your sysadmin lock you out of a system, Setup regular supervision(do not rely on informal meetings or drop in sessions), Don't worry about certifications or unnecessary documentation, Pay attention to what matters(actual system performance and DR planning).