Hi Lauren
I used to rent out a spare room in my house, and a few things I found useful were
Request rent to be paid by standing order to your bank account on the first day of the calander month.
Provide good storage in the bedroom eg flat pack shelves, drawers in mattress etc. This will mean that the tenant will have the ability to store all their personal belongings in their bedroom, and this will reduce the amount of their personal belongings stored else where in the house. Flat packs can be picked up quite cheaply in the likes of Argos, Atlantic home care.
If there are wooden floors in the bedroom, there are protector pads available that you can stick on the bottom of moveable items of furniture. I would stick some of these on the bottom of any moveable item of furrniture in the bedroom, as some tenants may decide they would prefer a unit of furniture across the other side of the room, and simply drag it across the floor.
When it comes to vetting tenants, I think it's just down to getting the right feel from the person. When someone rings up, I always say there are a number of interested parties, but let them view anyway. That way there is an easy get out route if you don't like them, as your can always tell them at the viewing that someone else already viewed the room and has first choice over them, and then tell them the next day that the room has been taken.
Paul