Don't have your warm drinks too hot - put a bit of cold water in so they're warm but not boiling.
Try some breathing exercises and vocal warm ups - going nyah nyah nyah in a sort of Tammy Wynette nasal twang can be helpful to get your voice back if it's gone (imagine singing along to Stand By Your Man and do the guitar bits).
When you feel your voice is very tired, try breathing out as hard as possible onto your own hand in front of your mouth and move your hand away, projecting your breath until you can still feel it at about 6 inches away. Then adapt how you're breathing so you can still feel it but not hear the breath sound at all. Those silent breaths open your throat out.
Once you've done that and got control back of your throat, take control of your vocal chords by trying to make a click with them without using your tongue - it's a weird thing but once you've mastered it you can get a lot more control when your voice is getting really tight. Try YouTubing 'glottal clicks' to hear the sound and see if you can replicate it.
Not an exercise but a behaviour change - try just pausing to breathe more frequently when you are speaking. Slow down and don't keep going on long sentences until you get out of breath. Think about how Morgan Freeman would say something and recreate his rhythms. This makes a big difference too!
If you have to raise or project your voice, take a big breath before you do so that you have power behind and don't strain.
I had speech therapy about 20 years ago when I was constantly losing my voice as a new teacher and those are the things that made the most difference to me. If you're lucky, a speech therapist with more up to date knowledge and experience will v be along shortly!