I'll share what's worked for me: Slowing down your speaking to an incredibly slow rate. Breaking down the word(s) into their respective sounds and elongating every syllable if possible. If I was to try and say BOOK (hypothetical problem word) then I'd say something like: Buuuuuuuuuoooooooooooookkkk. Or if I was to say a longer word like CABINET then it would go as follows: Cccccccccccccaaaaaaaaaaaaahhhhhhbiiiiiiiiiinnnnnnnnneeeetttttt. Almost as if you're speaking in slow motion. The idea is you lose the "punch" in the word and make it one long sound. Always do this on the exhale of your breath. As you're already prepared to elongate syllables when you exhale. Does that make sense? It's best to practice this when you're alone. Try read different sentences like this and you'll slowly develop a good feeling for the words. It's helped me a lot in my earlier years!