A couple of things off of the top of my head (and yes renting is a nightmare more often that not from our experience--sorry to tell you

):
Check the laws in your state and follow them all.
Get landlord's insurance.
Require (in the lease) that the tenant has renter's insurance and provides you with a copy of the policy.
Do NOT leave any utilities on in your name.
If you live where there is heating oil, put in the lease how much heating oil there is on move in and how full the tank must be when the tenant leaves.
Specify how many people maximum can be living at the home (we had three brothers who suddenly moved in their three girlfriends and 4 kids, which was way more than was appropriate to the house).
Search public records to see if the potential tenant has a history of arrest, eviction, bankruptcy, etc. Also call past landlords for references (though, as with jobs, they cannot legally tell you much so this is not all that helpful).
Specifiy, in wirting, what minor repairs are his responislbity vs, yours (yes, tenants will call the landlord to change a light bulb at times

).
Put in writing that the yard must be maintained to X standard and that if not a landscaping company will be called in and the bill sent to the tenant (mostly all you can do is insist grass be shorter than a certain length).
There is a lot more, but that is a good start. Also, if you start to realize it was a mistake, start eviction proceedings as soon as you legally can to not draw out the time they are in the house without paying more than absolutely necessary. It is a slow process.