Depending on where you live, the size may affect your property taxes.

If you just need electric for lights, a solar/battery setup may be easier than running a line. If you run a line and conduit, consider running a low voltage conduit as well, for alarm/phone/internet/cc tv/whatever.

If you might store a riding mower or other large device in it, make sure to make the door big enough.

Consider building it far enough away from the house so that if the shed goes up it won't take the house with it, and vice versa.