How can I prevent myself from yelling at my kids?

I am a college student and have one younger sister in high school and my parents would sometimes yell at us while trying to discipline us. I am really sick and tired of getting yelled at by my parents from time to time and honestly, yelling at me only makes me more aggressive. They even yell at me for getting undesirable grades (like I'd get yelled at for getting a B just because I didn't get an A). Unfortunately I have seen worse parents (who sometimes yell at their kids in public which is really disturbing). Chances are, that I am going to be a parent (father) and from what I hear, dads are usually the stricter ones than moms. I, however, don't want to yell at my kids because it would only piss them off regardless of whether they're 4 or 16 or 36. Is there other ways to deal with bad behavior? And how can I motivate them to be completely honest with me without yelling? I want to help and motivate, not hurt, my kids that I'm sure I would love so much. And when it comes to grades, I would like to have them show me their grades but I don't want to yell at them for getting, let's say, a C+. I want to help them raise their grade to, let's say, an A.