There are some simple universal excercises that are used by vocal coaches - regardless of the pedagogy studied -help prepare a students voice for singing. I list 7 of them below and they are exercises that I use to ground and prepare a vocalist’s voice for singing.
Like any discipline, they require practice, so spend at least 10- 20 mins a day using them at home.
NO SHOUTING is required in any of these exercise!

1.Humming as in bUMble - balances vocal cords. The first exercise you should do when warming up. Activation: bUUUMMMble bee
2.‘HUG’ - Open your vocal space by saying “hug” in your SPEAKING voice. Activation: Sobbing (pretend to cry or moan)
3.‘HALLELUJAH’ – Find your diaphragm and correct breath support for singing. Activation: Give God praise ‘HAAALLELUJAH’
4.Sirening on ‘oo’ as in bOOt - connect your registers and smoothes vocal breaks. Ascend and descend slowly. Activation: Think of an air raid or ambulance warning siren.
5.Ng as in ‘siNG’ - Improves pitch, makes its easier to hit high notes and locate head placement. Activation: imagine revving a motorcycle through your nose. Keep back of tongue high.
6.Nee Nay Na Noh Noo - Focus’ your tone to find a forward placement. Hold each note for 1 sec. Change the first letter to M and repeat. Activation: None.
7.8 note scale - sing an 8 note scale from C – C to improve Aural skills. Sing up and down the scale, and if you can, change the key. Use a Keyboard or Guitar. Activation: Do Re Mi Fa Sol La Ti Do
To Your Vocal Success