Even if you think you are born with the natural talent to be an actor, you will need some legitimate training to list on your resume and help you get jobs.  Find classes in your area to increase and practice your skills.  This is also a great way to meet other professionals and aspiring actors.  Consider a degree in theater from your local college or seek out classes at your local theater. Colleges with highly respected acting programs in New York include Juilliard, Columbia and NYU. Training programs are also available throughout New York City.  Some respected companies are HB Studios and Atlantic Theater Company School. Most of the shows on Broadway are musicals.  This means that not only must you be a good actor, but you will need skills in singing and dancing.  Find a dance school which offers training in all of the different styles of dance used on Broadway, including ballet, tap, and jazz.  The more well-rounded your dance abilities are, the better you will be able to adapt to the style of any show. Keep up with your dance practice.  You can begin to lose strength and flexibility if you don’t dance and stretch regularly. Once you can sing, dance and act, the theater world will deem you a “triple threat.”  You will be able to provide everything required of a Broadway actor.  The best way to train your voice is the personal attention of a vocal coach, who can find your range and fine tune your skills.  Look for coaches at your local colleges. Consider asking a music director to work with you personally. This will help you gain experience and build your resume.  Gaining experience onstage is important to growing as a performer, as well as creating a name for yourself.  If you are available for a role, take it and perform to the best of your ability, no matter the size of the part. The director is there to help you and the other actors come together to tell the story.  Listen to what the director says and perform your part.  Learn from every experience no matter how small the role may be. If the director is not giving much feedback on your performance.  Ask specifically for input.  Explore your role and ask questions about your character and performance.
Take acting classes. Learn to dance. Find a voice coach. Perform at your local theaters before moving to New York. Take direction well.