Id encourage you to gear up a bit first and foremost - buy a mask, cup, shin guards and even a padded shirt to wear under your jersey. Not only will keep your pretty face in one piece, you'll feel more confident playing defense out there.
*Assuming you are RH here
Throw backspin I find to be consistent I need to throw it with back spin, meaning my palm is facing down when I throw it. throwing with it facing up gives you top spin and less control. But alot of people prefer throwing palm up, I find I always go too deep.
Find a grip thats comfortable to you, personally I have small hands so I grip the seems with my fingers and let my thumb rest over the "hot dot" logo. Dont worry about knuckle balls, curves, spitballs until you have this down. I practice just sitting around and grip the ball and snap it out of my hand for that feeling.
Use the same motion, I start with my left leg back and my hands together in front of me. my left leg comes forward at the same time my right hand drops back to my hip. I then push off my right foot and release the ball just past my waist with a snap of my wrist to add spin and speed. I aim for 7-9 ft arc from about 18 paces (45 ft~)
Generally when Im warming up I try to focus on hitting it middle of the plate. Dont overthink it, its usually much more important to throw a strike and put him on defense then anything else especially in 1-1 ruleset.
Defense Be safe out there, as you finish your pitch, no matter where its going, get in a defensive posture. I usually have my glove up as I release the ball, it helps balance me anyway. Try to read the bat on weaker hitters and you can get a step that way to field a grounder
Direct traffic when a ball is in play. Read the play and act accordingly, on an outfield hit, try and backup either way. on any play to the plate, try to cover the backstop (without impeding the runner!)
Finally remember at most levels - pitching is at least 50% your defense behind you and 25% skill and probably 25% luck. try not getting too high when you have a good inning or too low when you have a bad one.