Watch yourself in the mirror as you sing. Pay attention to your own breathing while singing. Feel where your air is coming from when you push notes out.
Do a few exercises on your own. Push on your diaphragm slightly as you sing. Make sure you are pushing your voice from there and not from your throat. When pushing with the diaphragm, you'll notice a richer tone in your voice, and with practice, you'll see improved control and tone.
Locate a voice coach in your area. Check for flyers posted in music stores, coffee shops and venues for bands. Look for flyers and information at your school, college or university if you attend also.
Investigate by asking other people you know if they or one of their family members takes voice lessons somewhere. Question members of local choirs.
Know that you can take voice as part of most music curriculum at colleges and universities. Understand that the pressure is greater and grades are based on performance.
Find a voice coach you like to take voice lessons from--that's most important. Avoid voice instruction that makes you feel bad or unworthy. Change coaches or instructors if you get a lot of negativity from them.
Take voice lessons and enjoy singing more as you learn to control your voice and increase your range and ability.