Take singing lessons. As for anyone who aspires to sing, vocal lessons can be extremely beneficial in honing your voice to performance quality. This is especially true if you will be performing back-to-back sets or a full concert.
Join or form a local band. Whether you participate in a hometown garage band or start a group with your college roommates, getting some practical experience and figuring out what type of music you want to write and perform is a good early step.
Send a demo to a local radio station and see if they will play it. Maybe a DJ will like it so much he'll give it a spin. Offer the station a few free CDs for any contest they may be running, in exchange for some airtime. They may even want to do an interview with you.
Perform at clubs, music festivals and any other venue that can offer you needed exposure. The attention you get might include a nice review in a music magazine or a college newspaper. Network within the industry. Get to know other singers, musicians, producers and even entertainment reporters.
Know that some singers have literally gotten jobs working for music companies so they could get to know people who might be able to give them a shot by listening to their demo or CD. It might sound extreme, but sometimes to get noticed, you have to be willing to take a risk and do something bold.
Audition for a talent-seeking program. This option is more of a long shot than putting in the hard work to build a career over time, but if you believe you have the combination of attributes needed to be successful on a program like "American Idol," it can't hurt to try out. If nothing else, you have the opportunity to learn some things that might better your performances in the future.
Get an agent. As with other types of performers, having an agent can grant you access to opportunities you might not otherwise get. For example, an agent might get you a gig opening for a major act that could jump-start you music career.
Cut a CD and send it to music producers. While labels like Capitol and Atlantic receive countless new demos every month, getting noticed and signed by a record label would almost certainly make your career. For one thing, a record label, especially a larger label, will have the marketing machinery to put your name and your music out there in a way that you as an individual or group would be hard-pressed to match.