have you tried
1. toggle the vibrate switch. Does it vibrate when you press down? lift it up and down on a series of times to see what happend
2. plug it up to a charger. sometimes the sleep button or a home button doesn't work. Troubleshooting will start with there. If your volume switch is up, you'll hear it make the "charging sound"
3. Take it to an apple store, if it hasn't been taken apart or opened
4. If you've dropped it, you might of cracked the LCD and not the glass. Try the beginning steps first. Front glasses are between $30 and $70 for high end ones that are colored. This is the last step