Do you play any instruments? If you don't, then learn one, or hang around with someone who does. An instrument could help DRASTICALLY in your singing ranges. To start off, you should try playing simple notes, such as E, G, B, D, F. Those are the basic singing notes. When playing them on a guitar or piano, try humming along to the tune. Then, simple open your mouth, trying to create the same tune made when humming. You should make an "Aaah" sort of sound if you drop your jaw. Now, replace this "aaah" sound with an actual word, such as "cat" or "tree". Now, you'll be able to sing your first word. Keep practicing this method for about two days or so, then try moving to a different note. After you've mastered each note using keywords, try varying between those notes, switching from E to F, or G to B etc.
Next, replace these keywords with Do, Re, Mi, Fa, So, La, and Ti. As you progress through the notes, they go higher, Ti being the highest in most conditions. After you've begun your scale through the notes, try performing exercises such as:
Exercise #1
Do, Re, Mi, Fa, So! So, Fa, Mi, Re, Do!
Exercise 2
Do, So, Fa, So, Mi, So, Re, So, Do, So, Fa, So, Mi, Re, Do. And Repeat three or four times.
After you've done these exercises, you'll be more skilled in scaling, and you'll be able to tell what sort of voice you have. If you're a tenor, try hitting higher notes, such as Ti, to figure out your range. If you're a bass, then try hitting lower notes, such as Do, to figure out your range. Have a music teacher at your school tell you out what sort of singer you are, and try participating in musicals at your school and such. If your school doesn't support those, then try joining a music class such as chorus, or try singing with a band.
Lastly, after you've learned how to scale, and read notes and such, start searching Google for sheet music and download it. Try singing simple songs at first, then progress to more advanced ones.
