My way of patching a large hole in drywall is to use a drywall plug. A plug is simply a piece of drywall cut to the whole size with its facing paper left a little larger.
This extra paper along the edges keeps the drywall from falling through the hole and provides an edge on which you can apply joint compound.
With practice, you can finish a plug repair in a few hours. To make the repair, first square up the damaged area of the wall. Next cut a piece of drywall that is 3 inches longer and wider than the hole.
Working from the back of your patch, score a line 1 1/2 inches in from each edge. Snap these borders and peel off the plaster core, leaving the face paper on the front.
Apply joint compound to the paper edges and press the plug into the hole. As you smooth out the plug against the wall, press hard enough to push the plug flush to the wall, but not so hard that all the compound starts to come out from under the paper.
Allow the first coat to, dry; then apply two additional finishing coats of compound.For fast repair, try using a fast setting-type compound and a hair dryer to speed up the drying time.
To inspect your work, hold a lamp against the wall to cast light across the patch. Minor scratches and bumps will stand out. Sand out any scratches or apply additional compound as necessary.