Any good singing tips to develop a stronger singing voice?

Hold your breath. start for 10 seconds, then 15, then 20, and keep increasing until you can reach as high as you need to go. This will help you to hold long notes. do it about twice a day. Sing from your diaphragm. it should come from your stomach, your throat will vibrate a little bit, and your voice will be louder. PRACTICE, PRACTICE, PRACTICE! its pretty self explanatory. Learn to handle rejection. It doesn't really help you with your singing, but its a good skill to know. Have a lucky charm. if you're trying out for something, it'll help you feel more confident and you're singing wont be shaky, like it would be if you were nervous.

Learn to beathe properly. Also, find where your voice is strongest in note wise. Alto, Soprano, Mezzo Soprano, Baritone. I can sing all of these voice parts but am personally strongest in Alto. The higher i go my voice isn't as loud. So find where you are comfortable with. And don't try to push the notes too hard, otherwise they can turn off-key and flat.

Drink LOTS of water, practice, and you could take voice lessons =D Also, if you have a sore throat or horse throat honey helps. Learn to breath properly too!

Practice your scale, and this will sound weird, but, practice holding your breath, I want to become famous, and, well, it helps if you can hold the long notes. And practice with some one farther away then usual, and see if they can still hear you. Really hopes the helps you. :)