aight here are a few tips tht i learned frm my vocalist,
n his an awesome rock vocalist.

1. nvr drink ice water.
2. cut down on smoking. (improves ur breathing techique)
3. whisky actually improves singing for rock genre (no, im not encouraging u to drink)
4. practise the DO,RE,MI notes.. it really helps to hold a key
5. Honey doesnt work for everyones voice, so be carefull...
6. the proper singing techinque is singing by using the stomach not the throat
7. make sure u get proper rest b4 ur performance day, coz the voice does get tired if u dun have enuff sleep, or if uve been over training it. ( n profressional judges can tell this just by hearing u sing).

thts all i know lar..
i didnt say this is profressional advice.. just wat i know lar..
hope it helps.
take care... n all the best.