What I Learned as Area Governor
Most Importantly: get a staff. Note that I have a staff. You will learn that there is far more to do than you can do by yourself. You will learn how to delegate in this job. Staffs help represent you at meetings if you can't attend. Also, it's very courteous to attend each other's Area contests; it shows support. You, personally, may not be able to make them all, so a staff enables you to send a representative to the other contests (and announce your contest). Build your staff into a cohesive, fun, strong team. (Having dinner together can be effective.) Also, there's a very strong possibility that your successor will come from your staff. Start watching for who would make a good Area Governor, from among your staff and among the Club Presidents, as of Day One.
Whenever clubs have to send something to TI, have them send it by Registered Mail ("Return Receipt Requested"). Also, have them send you a copy; this verifies that they actually have done their task and have mailed it. Better yet, collect the item personally and mail it yourself.
Look ahead to deadlines, and avoid last-minute rushes whenever possible.
When clubs publish their rosters, ask to receive a copy. It's good to keep current on who is in your clubs. Talk to the presidents about who looks strong. Find things for aggressive members to do (Area Contest chairman, Area Contest Chief Judge, Area Contest Toastmaster, host a party, ...), and encourage them to keep progressing towards higher offices.
Have Officer Meetings monthly. Have the presidents give you their numbers for the month and tell you the latest news. Perform group problem solving to address their obstacles.
When you form your staff, try to have it represent as many clubs as possible. That way, if the officers of a club miss your Area meeting, then you'll still have someone from that club on your staff present who can tell what's happening.
Link your clubs. If one's having an activity, get it to invite the rest of the Area. Encourage members to visit the other clubs in the Area if possible. Are joint meetings possible? How about speaker/evaluator exchanges?