Try http://www.tape-finish-texture-drywall.org/drywall-hole-repair.html for repair info. This page has sanding info: http://www.tape-finish-texture-drywall.org/sheetrock-and-repair.html Good luck.
Depends on the size of the hole. Is the dry wall smooth or textured? I haven't checked those links myself personally but there may be good information in them. I personally don't think it is hard and have done some drywall work and patching on many occasions.
If it's small, then toothpaste will work. Just be sure to paint over it when you are done. It's a great way to clear up a wall that had a dart board on it if you are wanting to get your security deposit back, lol
You can cut drywall back to each stud. make sure to cut to the middle of each stud on each side then screw the ends to the studs. Cut new drywall and screw in place. Then tape the seams. They also have kits for small holes that you just put compound on and put patch over hole then more compound.