Sinker + changeup

Question
What are the best ways to throw a sinker and a change up. The change up is more important becuase I throw harder than most people. I started working on a change up a few months ago but never really got it down. Also I would like the sinker as an out pitch or even to start some of the better hitters who try to put that big swing on the ball so hopefully, if they do hit it, it wont go over the fence, but stay in the infield.
Thanks for the help.

Answer
The sinker is basically the same pitch as a two seam fastball. Depending on you arm angle the pitch will sink harder than others. grip the two seam like you four seam except place your middle and index fingers on or inside the seams at the "sweet spot". Thats where the seams are closest together.
For your change up, grip the ball like the 2 seam except place your middle and RING finger on or inside the seams at the sweet spot.
The most important thing is to throw them like your four seam fastball. This means that you should be trying to "throw it by" the hitter. They must think that the pitch is your four seam fastball when it comes out of your hand. lastly, be careful not to throw the pitch to someone who cannot hit your fastball. You'll be doing them a favor by throwing them something slower.
-Jon