Learning how to sing without voice lessons takes time and dedication, but it's not too difficult. All you need is patience and perseverance, and a room where you feel comfortable singing without censure from others. With a little self-discipline and some practice, most people can learn to sing without lessons. Clarity, proper breathing and enunciation will become a breeze--which is fortunate, as they are key elements to learning how to sing. Those things, along with developing your "ear,"--that is, your sensitivity to, and ability to reproduce, different musical tones--will set you on your way to singing in no time.
Enunciate your words clearly so that what you sing is understandable. For this, you need practice. First, find a page in a book to read aloud. Watch your mouth move in a mirror. Read as you normally would at first, but as you continue down the page, start reading more slowly. Pay close attention to each syllable as you enunciate it. Pay close attention to the way your mouth moves as you slowly and clearly enunciate your words.
Once you have read aloud to yourself, watch yourself in the mirror as you say tongue twisters, clearly enunciating every syllable: (1) Peter Piper picked a peck of pickled peppers. 2) Black socks, they never get dirty, the longer you wear them the stronger they get. Some day, I think I shall launder them, something keeps telling me don't do it yet. Not yet. Not yet. 3) She sells seashells at the seashore.
Harsh consonant sounds while enunciating, such as a hissing "s" or a "t" that sounds like spitting, are common. Make sure you enunciate them anyway.
Practice actual singing in front of a mirror. The best way to start is by singing the vowels A, E, I, O and U. Each vowel needs a different mouth configuration, which will help you learn mouth control and clarity of sound.
Begin with A by opening your mouth and pulling back the sides of your mouth into what might feel like a grimace. Sing "A" for five counts; then close your mouth a little more for "E." For "I," make a fist and make your mouth approximately the size of your fist, a little less of a smile, but wider than A and E. For "O," make a perfect "O" shape with your mouth, and for "U," pucker your lips as you sing.
Breathe when you sing. Most people have learned to breathe shallowly, but if you want to learn to sing, you must learn to support your sound with deep belly breaths. To learn how to breathe, place your hands on your belly and inhale through your nose. Imagine breathing deeply into your stomach. Feel it rise. This is how you should breathe when singing. Practice inhaling for five counts and exhaling for five counts.
Develop your ear, or ability to retain and accurately reproduce music or notes that you have heard, by playing a random note on a piano or electronic keyboard, waiting about 3 seconds, then reproducing the note with your voice. Check for accuracy by replaying the note as you're singing it. Try this exercise with random notes that you can easily sing without straining your voice.
Sing a song now that you have enunciation and breathing down. Pop in your favorite CD or tape that you want to sing to, and listen to it a few times to familiarize yourself with the words, tonality and harmony/melody of the song. When you feel comfortable enough, belt it out. Remember, practice makes perfect, so practice the steps, and you'll soon be singing with aplomb.
Learn to sight-read or read printed music by learning how to play the piano in tandem with singing. For free introductory piano lessons, see Resources.
Remember to breathe properly and only at regular intervals throughout your song. You will get better at this as you practice your breathing exercises and develop better lung capacity.