Learn the craft. You must learn to play, write and sing competently. Take voice and instrument lessons from skilled musicians and attend singer-songwriter shows. Learn to play your favorite artist's songs and think about what draws you to them. Invest the time it takes -- which can be years -- to learn the craft of songwriting before you even think about getting on stage.
Dip your toe in the water by playing your songs at open-mike nights, and make a fool of yourself at least 12 times. If the audience laughs only when they're supposed to, you're on the right track. Join a songwriting group, attend songwriting seminars and continue improving your craftsmanship.
Map out venues in your area, and realize that each venue is a business with its own needs. Only a few places you'll play will be focused specifically on music. Most music venues are restaurants, and their main interest is selling food and beverages. And frankly, most small music-focused venues are mostly interested in selling booze. Regardless, these businesses will only continue to hire you if they perceive that you can help them succeed. Some places will only offer you tips, and that's where you'll likely start. Research other venues like small festivals and -- especially -- house concerts. Avoid coffee shops unless you enjoy the backs of laptops, silence between songs and poverty. Try to play joints that serve alcohol; it puts your listeners in a better mood, and since you'll likely be getting free beer, the audience looks better, too. Seriously though, never drink more than one or two beers while on stage; it's bad for business.
Expect to make $50 to $150 per night in tips at a reputable venue. If you can build a following (even if it's only family, friends and people you met at rehab), you can find venues that offer $50 to $150 up-front plus tips -- and much more at house concerts. The average hourly rate for singers and musicians is estimated at $29.10 as of 2008, according to the Bureau of Labor Statistics. But to get the higher-paid gigs, you'll need at least two hours worth of material, references, promo sheets, posters, high-quality demos, online presence, e-mail lists, business cards, patience and evidence that you can attract fans who have access to credit.
Network with your fans, music critics and anyone who can help get you gigs. Get to know folks at your favorite music venue, even the ones who may seem unimportant. That guy who works at the door, who mumbles about conspiracy theories and reeks of blue cheese and cigarettes? He's your new best friend, the booking agent.
Invest in a well-produced and well-engineered CD when you're ready. Copyright your songs at the U.S. Copyright Office's website and understand that your first effort will likely not break even. You may never break even, so keep the day job. But if it's a good CD, it will help you get good gigs, and with websites like CDBaby, Tunecore and Reverbnation to help you market your songs worldwide for a pittance, the potential earnings are limitless. At the very least, if you're good, you'll have a shot at bringing in supplemental income of $25 to $150 an hour. And if you're good and lucky, some nights you'll experience the magic of a roomful of fans standing up and applauding your work.