You can buy theory work books from music stores.

For a singer, sight-reading depends on ear-training. You need to learn how to sing every interval.

If you don’t know what I mean by “interval” then go to a library and get a simple book on music theory (or browse for websites that teach you about intervals/music theory).

There are books that teach sight-singing and those would be the best way to teach yourself. Do you have a voice teacher who can help? Vocalists need a teacher, there is much about tone and placement that you can’t teach yourself, since your own voice will sound tonally different to you than it will to others.

Sight Reading can be very tricky. I was in my highschool show choir for 4 yrs and it was still one of my weakness, but with practice you can get by.

This website will help you practice your piano sight reading.

Here are some very basic steps you can take:

Learn the Four Groups of the Lines and Spaces:

Lines in the Treble “E G B D F”
Lines in the Bass “G B D F A”
Spaces in the Treble “F A C E”
Spaces in the Bass “A C E G”

In your case since you’re a girl only focus on the Treble cleff.

Practice drawing out your own staff and placing in the notes. My music teacher taught us a trick. For the Lines in the Treble recite Every Good Boy Does Fine that way you’ll always know is EGBDF. As for the spaces it’s pretty simple just remember FACE.

Good Luck! and keep practicing!

You can’t teach yourself how to sightread. You need for someone to tach you music theory.

i would say practice with a piano – press a key and the sing the tone. after doing it for a while you should be able to start making the connection. other than that, practice practice practice!