Don't Kill Your Voice Before You Perform
You have been there before when you are at a venue before your show starts and your screaming just so others can hear you talk. On the ride over you were probably yelling over music too. Please stop this immediately, your voice will thank you later. Yes I know this can be extremely hard to do and almost seem impossible when you have people trying to have conversations with you in anything but quite places but it will be well worth it. Some nights will be harder for your voice than others but you'll need to figure out when there are opportunities for you to preserve your voice for your performance.
There is always a quiet or relatively quite spot at any venue, your job is to find it immediately! That is the place you need to sit when you are finished your sound check and you have already greeted any new visitors. If you feel you absolutely need to be quiet for a second during your break work the crowd a bit, go to your merchandise table and then give yourself 3 minutes to head over to the restroom. I half jokingly tell everyone who knows me that potty time is sacred time. Few people will stop to talk to you if they know you need to use the restroom and will kindly let you head there for some you time.
Also, take turns with the other members of your band, if you are not a solo act, talking to people when your voice is almost done. By no means do I mean for you to just dismiss people, you would not do that under any other circumstance and you shouldn't do that now. What you can do allow other members of your band to answer a question that is common knowledge for all members. I will say some things like when is the next time you'll be playing someone may want to hear directly from you if they already feel they have connected with you. Tell them and then include another band member in the conversation so you can talk less. After the show I'd say it's worth it to use your voice until you leave. Be nice and continue to engage with people until either you leave or they do.
Pay attention to what you eat and drink before your performances as well. Nothing is worse than burping, having heartburn or stripping your vocal chords with glasses of alcohol before a performance. Yes, I'll say have a drink if you would like before a performance if you would like, just don't go overboard and don't get something that will finish you for the night either!
Every performance you give should be memorable and you want people to remember them for good reasons, not because it was so bad that you used your voice up and couldn't finish or finish strong. Preserve your voice as best as you can while engaging with your audience and they will appreciate it.