The one thing to know about witchcraft is that it's totally nonlinear!
Some witches incorporate dogma and deities into their spirituality; others don't. Some witches prefer working with herbs and plants; others focus on crystals. There are many different branches to witchcraft; for your own edification, it's important to dabble in different areas, just to try them out and see if they're for you.
Personally, I'm a secular witch who focuses on divination (Tarot, astrology, palmistry and crystal ball gazing) and crystal work. A few years ago, I never thought I'd be interested in Tarot, let alone that I'd get consistent, clear messages and advice from the cards- but, I decided to try it out one day and immediately felt an unexpected, divine spark. Don't knock anything 'til you've tried it!
Safety first, boils and ghouls!
Before you start dabbling, it's important to know how to protect yourself from negative energy/bad spirits/whatever negativity you may believe exists. There are at least hundreds of ways to do this, from using burning sage to cleanse yourself, objects and spaces to using certain crystals with protective properties. You can say prayers or chants to protect yourself, while others like working with salt, drawing sigils or imagining protective white light surrounding them. Research different methods and do what rings true to you!
On The Dark Arts
While I'm dishing out warnings, I'll say that the one aspect of witchcraft that I don't think I'll ever touch is dark magic. I've no interest in trying to curse people or attempting to upset the natural balance of things by influencing things negatively, and I don't want to speak with potential demons/angels/spirits. I'm not at all trying to shame witches who do dabble in dark arts, I just feel that they're not for me. I don't want to put that kind of negativity out into the universe.
I don't even use witchcraft to try to influence events in my own life; I only use it to give myself strength, power, peace and advice. I believe that the universe unfolds as it should, and that it's unwise to try to disrupt The Fates.
All I use witchcraft for is to empower myself and give myself the emotional tools I need to handle what life dishes out.
Real-world witches aren't the warty, ugly, mean-spirited things Hollywood usually depicts; we're real people who are simply following our own spiritual paths intuitively. Witchcraft has been a completely positive force in my life.
If you're interested in witchcraft, I encourage you to experiment with it and figure out which branch(es) of it suit you, but remember to stay cautious and protect yourself from negativity when doing so! Witchcraft is all about intuition and doing what feels right to you. Listen to your inner voice, experiment and have fun!