I will be playing a villain in a play, but I'm just too nice. How I can I get into an evil character without hurting anyone?

But ... but ... but - this is what ACTING is all about. SURELY you know that.

Pretend that everyone is out to get you. You are the misunderstood victim, eager to show the mofo idiots that you're not only smarter and better than them but nastier too.

Why in the world do you think you’d have to hurt someone to portray a character?  When people talk about “becoming a character” they don’t mean you literally become them. It’s still acting.

Developing an “evil” character is no different then developing any other character.  You breakdown the script into beats and ask who am I? Where am I? Where am I going?  From there you can work backwards to create a backstory.You also look for the character’s objectives, stakes, and obstacles - what does the character want? Why should the audience care about it? What is in the way of the character reaching their obstacle.Don’t look for some shortcut or trick to playing “evil”.  You’ll end up with a flat, unbelievable character.  Put in the work.

Good luck.

Something that may help you: most people don’t deliberately set out to be bad people. Sure there are some that do, and revel in being different and evil. 

But most people go about their lives believing that they have made the best choices they could. If you can figure out how to frame your characters actions so that they seem like good, reasonable decisions, then you will be making strong acting choices.

1) How and why did you land this role? What did you do in the audition? What did they see in you, why were you the best person to portray this character in the first place?

2) Take acting classes.

Look. I'm gonna give it to your straight. You may have gotten lucky with your audition. Maybe there weren't other options, maybe it's just a school play and it's nothing serious. But when it comes down to getting a role, any role, this is when your experience and training comes in handy. That's why serious play productions and actual threaters prefer taking experienced people who've been studying acting for a few years. This is why getting a leading role even in community theater is hard without a nice-looking resume under your belt. Because otherwise THIS is what happens - they get "actors" who don't have any idea what they're doing and think asking strangers online will give them the answers. It doesn't work that way. Tips are not enough. There's a reason why people study acting for YEARS before becoming pros. Before any legit agent can consider them. 

I may be preaching, but you need to hear this. I'm hoping for you that this is just a school play, so just rely on random tips for now and hope for the best. But if you're serious about acting, you need to get into a *good* acting school. You need actual guidance and interaction. If you're already in acting achool, find a better one. This is the kind of stuff they're supposed to prepare you for.That's what acting is. You're not supposed to portray a character like you or vice versa. It has NOTHING to do with who you are. It's all in the PROCESS, from getting a character to portray to portraying it on stage.

Get to work. 

You have to work on setting aside how you would behave and get into the mindset of the character.  Try to look for a villain who is both good and bad at the same time.  Is the character one who tries to do good but lets other things get in the way?  In other words the best villains are the ones who are 3-dimensional.  As an example in modern pop culture Darth Vader was a combination of both good and bad.