Okay, I'm a singer, I can help with this.
1. Smoking and drinking fuck you up. Don't do it before a gig, and do it as little as possible the rest of the time.
2. Anything dairy coats your throat and so ruins your projection and sustain. Try to have as little as possible in the days leading up to a gig. Drink water instead of other stuff as much as you can or want to.
3. 'Biting the mic,' whether you were kidding or not...don't go close to the microphone. Microphones are made to catch sound from like, a conical area, and you don't need to go as close to the mic as say, Ian Curtis or Liam Gallagher do, with their mouth actually touching it. This is unnecessary, bad for the microphone, and makes you sound like crap.
4. During the solos, it depends on what kind of singer you are. It sounds dumb, but I tend to like, dance. Not in a dumb way. In a way I would while I was singing, just without singing. Or you could just get some water
5. Stand up straight, stick your chest out, and pull your arse in. It helps you project. Think the way Robert Plant or Paul Rodgers stands when doing one of their big notes. The leaning back? They do it a bit extremely, but to a lesser extent than they do it it actually is helpful.
6. I've never had singing lessons, so as far as improving range or warmups I can't help you professionally - but I can tell you one thing, my range has improved immensely over the last few years by gently pushing my voice. Songs that are JUST within my range on a good day, that I can only JUST reach and it's a bit of a strain (but NOT painful, if something hurts your voice to do, don't do it, at all, and that includes screaming for a metal band if that's your forte; that requires training in how to breathe and where in your body to pull the scream from) but I can just get it. After a few months of singing that same song, my voice would adjust to that level slowly, and sooner or later it would become comfortable for me to sing it. Then I could move up further. With this method, not only have I outsung a choir on my own, but my range is now way, way wider and I can sing falsetto. If you've heard my speaking voice, that's miraculous.