You don't mention what type of boat you have. If you have an inboard, for example, you don't want to just ignore it. You should turn it over (either by hand or with the starter) to keep things lubricated. If you start it, then you must have water running through it, so make sure you do it right. If in a place where it will freeze, then after you start it, you need to winterize it before winter sets in. It is a good idea to squirt fogging oil in the cylinder to keep the rings lubricated as well. The fuel tank should be filled so no condensation develops and you should put in a fuel additive so it stays good. If you are out of the water for a very long time, it might be advisable to remove the fuel and start with new. The boat should have ventilation going through it so it doesn't get all wet and moldy inside for condensation. This is even more of a problem in a place like Florida - especially if you are inland like at the Indiantown Marina up the river from Stuart (for example). Inland, during the hot summers, it gets really humid in areas like that. If you just ignore your boat for long periods, then when you return you will have a living ecosystem to deal with. Keeping the sun off of it is a good idea, but not so the deck gets so hot that it cannot breathe. That will also ruin any bright work you might have on the exterior. Boats are happier when they are used and cared for.
