Here are some tips that will help you develop a good singing voice:
1. Relax your vocal chords before you start
Strained vocal chords mean you won't hit high notes well. Try saying "Mum... Mum... Mum..." in different tones instead of "do re mi." Warm up for at least a few minutes.
2. Don't force the high notes
When you do need to hit a high note, don't try too hard or tighten up. Relax and let your voice rise smoothly, but still maintain control. If you force your voice, you will end up hitting a bad note.
3. Drink plenty water (not iced) or have warm tea
This is best for your vocal cords because it simply hydrates them and helps clear away excess mucus. Cold water will shock and tighten your vocal chords. Avoid milk, soft drinks, and other similar drinks because the lactose in milk and the other sugars in soft drinks cause phlegm and mucus to build up in your throat
4. Practice breathing deeply
Make a habit of breathing from your diaphragm instead of gasping and/or heaving with your chest for air. If you are breathing properly, your belly will expand, not your rib cage.
5. Practice phrasing
The right time to breathe while singing is between phrases (word groups sung together). In ordinary writing, phrases are often set off by commas or other punctuation, but punctuation may be absent from lyrics. Look over the lyrics before you start singing. Figure out where the natural pauses or breaks are. When singing, take breaths at these breaks. You have to practice phrasing/breathing so that you can sing without straining, gasping for breath or running out of air.
6. Record yourself
Record yourself while singing to see whether your voice sounds pleasant or irritating. Listen to your voice with an open mind, and don't try to convince yourself that it sounds right, if it really doesn't.
7. Improve and experiment
Try to make your timing and phrasing fit the song better. Experiment with varying amounts of nasal and chest tones, timbres, accents and styles to see what suits you. Have a good friend listen who can give you constructive and helpful criticism.
8. Practice singing in front of people
Looking at people while singing may feel awkward at first, but with practice you get used to it. If singing in front of others makes you nervous, try looking at their foreheads or over their shoulders. Practice singing in front of a mirror before you perform for an audience.
9. Be open to criticism
Try performing before friends or family, whichever you feel more comfortable with. Family members will usually try to sugarcoat reactions and not tell you their true opinions, while good friends may be more open and free with their thoughts. Be ready to laugh at yourself.
10. Enjoy yourself, show confidence, have some fun
11. Be persistant
Talent helps, but persistence is more important! Keep on developing your song list, vocal techniques, voice strength and stage presence. Keep on learning to "sell your song" to the audience, using hand motions (a hand on your heart, temple or pointing to the heavens, walking a little, each at the right moment), with sincerity, maybe a slight "tear" of sorrow in your voice or humorous timing as fits each song. Just don't give up.