Things I've learned about the voice/ singing in just two months of working with a vocal coach.
Epiglottis: Basically a lid to your larynx that protects your trachea when you swallow liquids or eat. Redirects food to the esophagus. Closes like a trapdoor. Can be used for distortions in a more lighter growl or minor grit in pop or some rock music.
Arytenoids: Muscle that helps move the vocal folds. Used for distortion in a death metal low growl or scream.
False folds: Line the true folds on either side. Help to close the glottis. Thicker than the true folds and are used in distortions for many classic rock or pop songs.
True folds (vocal folds): As big as a pinky nail. (That's pretty small chief.) Thicken in more chesty and strong sounds and thin out in breathy quieter sounds. Lay horizontally and can stretch like a rubber band. Close together when engaged.
Larynx: The entirety of where these muscles and glands lie. Moves upwards during bright sounds and down in warmer/ heavier sounds.
CT muscle: Pulls the thyroid and cricoid together. Activated in higher pitches.
Fry: The scratchy register below the chest voice, engaged by (false folds?) Found by gradually decreasing volume or lowering pitch.
Chest voice: Resonates in your chest. Vocal folds will thicken. Use your speaking voice on pitch with a touch more added volume. Exercise words: Go, Bye, Hey, ect..
Mix: The register between chest and head. Used in more musical theater and contemporary styles. Found by holding back on volume and finding brighter and sometimes brattier sounds. Exercise words: Naaah, bay, Meow, Gig, Nyeenh, ect... Avoid spreading too much unless you're higher in the range.
Head voice: The register above your mix. Used a lot in musical theater or classical music. Found by raising soft pallet and making small contained sounds. Resonates more forward, or higher. Exercise words/ sounds: Any constant with “ooo” after it is a good one or a tall "Ah" Drop the jaw when you get high but avoid spreading the mouth too much until you're in the extremes.
Flageolet: The register above head voice. Where your voice wants to crack. Squeaky, whistle sounds. Exercise words/ sounds: Work your way up with head voice sounds especially "Oos" until you start to crack or squeak. Keep the vowel tiny and do not drop the jaw.
Lowering the larynx: For when you want warmth or more dark sounds. Yawn to move the Larynx down originally. Dumb down the voice like Patrick Star in more extreme cases, or use a very tall and dark "Huh" or "yuh"
Lifting the larynx: For when you want brighter more light sounds. Imitate SpongeBob for more extreme cases. Use sounds such as ayyy, or eee.
Singing more quietly: Use less air overall. Practice a controlled hiss
Singing louder: Use more air overall. Practice a more pushed hiss
Expanding your range: Use the tiny “ooo” sounds in the Flageolet section starting with a head voice and gradually moving upwards.
Using less breathiness: Do a short staccato "ee" or "eh" sound through range which will activate the glottals resulting in less breathy sounds. Also look into a more chest voice sound.
Using more breathiness: Sigh through your range, use words with an extended quiet "h" in front of them. Ex: "Hey" in a sigh.
Belting: Volume does NOT need to be super loud. Slightly louder than a normal speaking voice. Much like the chest voice except you can take it higher. The stronger you start with, the easier it is to keep. Use short staccato words, ex "Gig" and avoid spreading the mouth too much.
Whistle register/ tone: Vocal folds do not engage. Found by inhaling on a very high pitch with mouth rounded and tiny. Ooh or Ahh sounds good for this. Then use the same feeling in an exhale.
Melisma/riffs and runs: A stylistic choice usually done in very similar major or minor pentatonic. Can be found by slowing down the specific run/ riff to get each note and practicing on a laughing sound "ha." Gradually speed up this sound as you get used to it. Apply the real sound/ phrasing/ words from the song after you're comfortable with this.
Epiglottic: Make a Ms. Piggy sound "mmmm". Carry that feeling through your range.
Arytenoid: Do a heavy sigh like you just got home from work after a long day or you're annoyed. A cough feeling also works. Carry that feeling through your range.
False Fold: Pretend you are lifting a heavy object. Use Hey or yeah with that feeling and carry that through your range
Jaw tension: Massage the jaw, puff up your cheeks as you sing. "Bwub" is a good word for releasing jaw tension.
Tongue pulling back or tension: Stick the tongue out while you sing to get used to it first, then try to keep the tongue relaxed at the bottom gum line behind your bottom teeth.
Neck tension: Move the head side to side
Mucus/phlegm in the throat: Stay hydrated, drink water, gargle water, do a lip bubble, avoid clearing your throat too often. Avoid certain foods and beverages that you know affect you, for example dairy in some people.
Breath support: Inhale low into your abs and release a controlled hiss, “shhh” or “vvvv” sound. Lip bubbles are also good for it.
Posture: Keep your ears horizontal above your shoulders and stand up straight. Avoid lifting the head. Lay flat on the floor or stand up against a wall to help you find proper posture.
Staying hydrated: If your throat is feeling dry, drinking water right then and there isn't going to immediately help. Water takes hours to reach the vocal folds. A nebulizer or humidifier can be instant relief but don't rely on it all the time. Drink water throughout the day.
Coffee: It isn't inherently bad for the voice as no liquids actually pass over the vocal folds as you drink them. Just make sure you supplement it with water as it makes you have to go to the bathroom which dehydrates you.
Avoid alcohol. Unless you're drinking a lot of water with it. It dehydrates you, plus your inhibitions and judgements are impaired so you might not be able to focus on how you sound, or what techniques you are actively doing.
Fatigue/ pain: If your throat hurts or you're in pain when you sing, you're doing something wrong. See above tips and take a break if needed.
Voice recovery from illness or injury: Rest. Hydrate. Quiet humming or lip bubbles, light breathy sounds, quiet “oos” etc... Talk to an ENT if necessary.
Anxiety: Do some hisses, do a half bend and allow your muscles to hang and relax, do some quiet breathy exercises such as "vshh" or "hnng" on a slide.