There are many different schools of Buddhism with a huge diversity of teachings and practices. How do you know which one is right for you?
The many schools of Buddhism employ different skillful means (upaya) to help people realize enlightenment, and they explain Buddhism in many different ways. Some traditions emphasize reason; others devotion; others mysticism; most combine all of that, somehow. There are traditions that stress meditation as the most important practice, but in other traditions people don't meditate at all.
This can be confusing, and in the beginning it might seem all these schools are teaching entirely different things. However, many of us find that as our understanding grows, the differences seem less significant.
That said, there are doctrinal disagreements among the schools. Is that important? Until you've practiced for awhile, it's probably unproductive to worry about fine points of doctrine. Your understanding of doctrine will change over time, anyway, so don't be too quick to judge whether a school is "right" or "wrong" until you've spent some time with it.
Instead, consider how a particular sangha feels to you. Is it welcoming and supportive? Do the talks and liturgy "speak" to you, even if on a subtle level? Does the teacher have a good reputation? (See also "Finding Your Teacher.")
A more critical problem for many in the West is finding a teacher or community of any tradition near where they live. There may be informal groups in your community who meditate and study together. There might also be Buddhist centers close enough to visit in a "day trip." Buddhanet's World Buddhist Directory is a good resource for finding groups and temples in your state or province. Start Where You Are
The dharma center near you may be of a different school from the one you've read about that caught your interest. However, practicing with others is a much more valuable experience than reading about Buddhism from books. At least, give it a try.
Many people are shy about going to a Buddhist temple for the first time. Further, some dharma centers prefer that people receive beginner instruction before they attend services. So, call first, or at least check the center's website for their beginner policies before you show up at the door.
You may have friends urging you join their dharma center and practice as they do. That's great, but don't let yourself be pressured into joining something that doesn't feel right for you. It may be that the practice that works for your friend is all wrong for you.
One of the foundational teachings of Buddhism is anatta, or not-self. The Buddha taught that what we think of as "I" is an illusion, and our dissatisfaction or unhappiness (dukkha) comes from clinging to that illusion. A stubborn refusal to practice with others is symptomatic of self-clinging.
That said, many people find themselves practicing alone because they live far away from a temple or teacher. If you can manage even one weekend retreat a year, go. It can make all the difference. Also, some teachers are willing to work with long-distance students through email or Skype. Why Do I Have to Choose?
"Spiritual transformation is a profound process that doesn't happen by accident. We need a repeated discipline, a genuine training, in order to let go of our old habits of mind and to find and sustain a new way of seeing. To mature on the spiritual path we need to commit ourselves in a systematic way."
With commitment, working through doubt and discouragement, we drill deeper and deeper into dharma and into ourselves. But the "sampler" approach is like digging 20 one-foot wells instead of one 20-foot well. You don't get very far beneath the surface.
There are Buddhist cults as well as phony teachers. People with little to no background in Buddhism have passed themselves off as lamas and Zen masters. A legitimate teacher should be affiliated with an established Buddhist tradition, somehow, and others in that tradition should be able to verify the affiliation.
This doesn't necessarily mean the "legitimate" teacher is a good teacher, or that all self-taught teachers are scam artists. But if someone is calling himself a Buddhist teacher but is not recognized as such by any Buddhist tradition, that's dishonest. Not a good sign.