Hmmm...
Well, 'get a trained voice teacher' is the best answer. But in lieu of that, I just asked my voice teacher on MSN what he thinks. God, this is so hard to explain...
Firstly, you need to ensure that your muscles and false vocal folds (a set of folds that lie above the real folds to kinda protect them)in your larynx are fully retracted. To do that, try doing big, deep belly laughs like Santa Claus. While you're laughing, feel the sensation of openness in your voicebox. That feeling of space and openness is being retracted. By practicing that laughing exercise you can eventually learn what retraction is and be able to retract instantly and constantly without needing to laugh or think about it. By retracting you're creating a good space for resonance and you're also preventing any excess friction on the vocal folds, thus preventing fibrosis of the folds which is essentially nodules.
Secondly, when you belt you should ensure you're body is properly anchored... Anchoring is a great technique because it helps you sing safely, as well as singing 'better'. I always anchor when I'm gonna go for a big note or a note at the top of my range because it actually helps you maintain a note for longer and helps you reach higher. It's also important in protecting your voice from misuse.
Basically, if the muscles in your larynx are tense or tight, you're less like to produce a nice sound and you're more likely to damage your vocal folds by placing them under undue stress. If you haven't stretched or warmed-up before a performance, or you'rw a bit uptight, your larnyx will be tight. Anchoring works by deflecting tension away from this area. In essence, anchoring involves consciously tensing muscle groups in your body to divert the autonomic tension from your larynx. It's good to control your stomach muscles (like you're trying to show-off your six-pack) anyway as this will support your diapharagm and help maintain control over your breath. You can also clench your butt cheeks and my favourite technique is to imagine i'm trying to hold two oranges in my armpits and keep them there with my arms at my side by using my chest muscle. Kinda like you're striking a bodybuilder pose and you're demostrating your pecs. SO when you sing, clench your muscles and that'll help ease off pressure on your voicebox so the note will be easier and you'll sound better.
Third tip, if anything ever starts to hurt, STOP! If it hurts, you're doing something wrong. Rest your voice.
When my teacher told me those two tips, it really transformed my singing (I sound like a born-again Christian). When you start to use those techniques you'll be able to make better sounds and actually you'll realise your range is way bigger than you thought. When my voice broke I had a few years of cruddy teachers and my voice was poo. Then with a bit of good teaching, I realised I had about 3 extra tones on top of what I thought I had. So get practicing and use your new found skills!
Mind you, none of this is substitute for a real, trained voice teacher so work on your parents or get a job.
"Jane, I've been dealt a blow - I've been dealt a blow, Jane."