Plenty of other people gave links to tutorials, and those are all fine. I wanted to emphasize that this is a skill that takes time, effort, a good amount of practice, and play to get comfortable with.
I think too many people are scared of learning a skill, and want tutorials to guide them through the process. There was a post a week ago about an app trying to teach people how to cook by asking them to find a picture of a "scrambled egg" in a line-up. Obviously useless, and that doesn't get people any closer to what actually needs to happen -- just pick up a pan and try. No, you won't get it right the first time. Nobody does. That's what the practice is for.
Start by actually starting.