Hint: Remember to relax the jaw, the tongue, neck, the shoulders and the rest of you. I see tension, people! And therefore, I hear it. Breathe. Ahhhh.
Kathleen Hansen Vocal Warm Ups
Subscribe to her YouTube is highly recommended. Here is the link to her channel, she has FANTASTIC VIDEOS. 12 minute warm up, breathing, resonance, all sorts of things:
https://www.youtube.com/channel/UCpNH0HrqqBmPscbSxe4qEDQ
Others:
Straw warm-up – great for tired voices or anytime. Relaxing.
https://www.youtube.com/watch?v=0xYDvwvmBIM
More from Ingo
https://www.youtube.com/watch?v=D4wcA0RpDUQ
Renee Fleming on legato singing:
https://www.youtube.com/watch?v=d-Pcf-M5L80
Tony Leach – choral warm up
https://www.youtube.com/watch?v=4Yu5uJ-1oIM
James Jordan, Westminster Choir College
https://www.youtube.com/watch?v=v2zWZQ4f2zs
Choral Warm Up – Roger Hale
https://www.youtube.com/watch?v=tnJW-8a26OA
Help for singing in tune:
https://www.youtube.com/watch?v=ECdeg_RmdWk&feature=youtu.be
Other vocal warm up by Roger Hale
https://www.youtube.com/watch?v=BolHK6VZR38
Music Theory and Ear Training
https://www.musictheory.net/lessons
https://www.teoria.com/