It truly is a lifetime path to discovering your true voice and one that doesn’t necessarily ever end. You can never have enough voice training when learning to sing so seek out coaches and training whenever you can.  For the lifelong singing student, here are a couple of tried and true tips:

A Tight-Rope Act: Flex Some Muscles While Letting Go of the Rest
Singing is a lot like patting your head and rubbing your stomach at the same time - its more about coordinating multiple things at the same time. You have to keep some of your muscles completely relaxed while strenuously pushing different muscles to their peak. You should be able to keep your tongue, jaw, throat and shoulders completely relaxed while focusing all of your tension on the diaphragm. Do not use your shoulders or your throat for any power, this will only constrict your voice.

Singing Myth: More Air Means More Volume
To sing louder, many people try to focus on using more air behind their voice.  Much the opposite is true - this only makes your voice more quiet. Exactly like whispering, your voice will actually soften if you release the air out of your mouth before it has a chance to hit your sinus cavities. The volume in your voice really comes from resonating and reverberation throughout the cavities in your body instead of breath.

Journey To That Tricky Diaphragm
If you don’t know where your diaphragm is, here’s a way to discover where and what it is. First, put your hand just above your stomach and right below your rib cage - this is called the solar plexus.  Then, let all the air go from your lungs.  When you think you’re done, push still a little more.  Can you feel it tighten? That’s your diaphragm getting tired. If you still can’t locate your diaphragm, you might want to try Singing Success for more exercises like this.

Get Your Voice Revved
Before you try to hit those upper tones at the top of your range, make sure you’ve properly warmed your voice up. Your vocal range increases the warmer your cords get, and you’ll be able to hit higher and higher tones. If you go for tones that are too high, too soon, not only will it sound horrible, you’re putting your cords in risk of being damaged. If your throat starts to get a little soar - STOP - gently sing lower pitches until you are sufficiently warmed up. If you really want to take your vocal range to the next level, check out Singing Success for more in depth information

Keep these tips in mind as you craft and perfect your voice and singing style. Keep the right muscles relaxed while focusing on the diaphragm, don’t put too much breath in your lungs (just about as much as you use when you’re speaking), and be sure to sufficiently warm up before hitting the tones in your upper register.  Also, work with a vocal teacher or an instructional course like Singing Success by Brett Manning to keep your training active.