Reddit mentions of Boosey and Hawkes 333 Elementary Exercises - Zoltn Kodly Choral Method

Not an actual choir teacher but an instrumentalist who has benefited immensely from learning solfege.

-Make sure you learn the curwen hand signs in conjunction with the syllables!

• I recommend movable 'Do' not fixed
  
  
  
• When singing in the minor mode, use 'La'
  
  
  
• buy a tuning key in A=440 and every day hold it, sing A as best you can and then check your tuning with the key. Always try to pull your pitch reference from your own head and THEN check to see how close you were.
  
  
  
• Start by picking some of Kodaly's group sight-singing books. They're designed specifically for use with solfege/hand signs.
  
  https://www.amazon.ca/333-Elementary-Exercises-Sight-Singing/dp/B003AGJK6G/ref=sr_1_2?ie=UTF8&qid=1523271184&sr=8-2&keywords=333+exercises
  
  Also, get 'Let Us Sing Correctly'
  
  https://www.amazon.ca/Let-Us-Sing-Correctly/dp/B000ZGCLN8/ref=sr_1_1?s=books&ie=UTF8&qid=1523271216&sr=1-1&keywords=let+us+sing+correctly
  
  The first book is just the pentatonic scale. No 'Fa' and no 'Ti'. That is to say, no half-steps (which are the hardest to tune). I promise you, if you have a good foundation of sight-singing the major/minor pentatonic scale, you'll be well on your way to reading any tonal music. Adding in those half-steps later will be easy.
  
  
  
• It's not about total time practiced, but how frequently you do it. The more the better.
  
  
  
• Remember, your only real goal here is to memorize the sound of intervals and be able to reproduce them easily - everything else is secondary.
  
  Hope that helps!
  
  The second book is to help with tuning and harmonizing. I practice it with my right hand playing one part on the piano and singing the other part.