How I Install Crown Molding By My Self?

You will need to cut the molding for the corners at a 45 degree angle so that they will butt up in the corners. Not all rooms are totally square, so you will need to know how to use a T-square.
You will need some finishing nails to install the crown molding.
   You can also purchase inside and outside corner cornices, nail them up with finishing nails, then butt the crown molding right up to them. No need to miter. They look good and it's a lot easier. Especially if you have never installed molding before.

If you have a miter saw, its pretty easy, just measure and cut to the very outside of your measurement  and cut corners at 45 degrees. Youre best painting it before you cut it as its easier