If you're getting ready to pull your toilet for repair or replacement, you should drain both the bowl and the tank. If you don't, you'll spill water all over the floor no matter how strong you are and how carefully you handle the toilet. It would be nice if you could simply pick the toilet up and pour the water out, but since you can't, use a couple of tricks to make draining it easier.
You need to drain the tank before you disconnect the water supply, or you'll have a minor flood. Turn off the toilet shutoff valve, then push down on the flush handle and hold the handle until water stops draining into the bowl. About an inch of water should still be covering the bottom of the tank, so use a sponge to soak it up and transfer it to the bowl. When all the water is gone, it's safe to disconnect the water supply hose, but keep a rag on the floor because a small amount of water will drain from the hose.
Although it may seem counterintuitive, the best way to reduce the water level in the bowl is pour in more. Fill a 5-gallon bucket with about 2 or 3 gallons of water and pour the water quickly into the bowl. The large volume of water flowing rapidly into the waste pipe creates a suction that flushes most of the water out of the bowl, and because the tank is empty, no water flows in to replace it. You can't get rid of all the water in the bowl this way, but you can significantly lower the water level.
Once you've lowered the water level in the bowl, the easiest way to remove all of it is to sponge it out. Don't do this unless you're absolutely sure you're going to pull the toilet because when you empty the toilet trap, you create a direct air passage to the sewer, and nothing will stop the gases from wafting into the bathroom. If reaching into the bowl with rubber gloves and a sponge seems too unappealing, use a sponge mop. Dip the sponge or the mop repeatedly in the bowl and squeeze the water into a utility bucket for disposal. You can also empty the bowl by repeatedly plunging with a toilet plunger.
If you're in a hurry to get the toilet off and out of the bathroom, there's nothing to prevent you from doing so while it's filled with water. Expect spillage along the path to wherever you plan to empty the water. When you get to that place, which preferably is on the lawn or a gravel walkway, set the toilet down upright, then tip it gradually backward until it's lying on the back of the tank. Tip it slightly more to completely drain the tank, then set the toilet upright again and tilt it forward until its supported by the front of the bowl and the top of the tank. This maneuver completely drains the internal trap.