Making the "w" Sound
Many of my Indian, German, Chinese, Korean, Middle Eastern and other clients find the "w" sound in English to be especially challenging. The advice I give is this:
To make the /w/ sound, you're just rounding your lips and blowing air with sound (voice) out of your mouth. Your teeth are not touching the bottom lip. The tongue just stays in the middle of your mouth, not touching anything.
When you see a "w," say "Oooh," as in, "Oooh, nice haircut!" So when you see "What?" go into it with "Ooowhat?" The same for "Ooowhere?, ooowhy?, ooowhen? When you get the feel for what you're doing, you can pull back from so much "Oooh," and eventually you will forget how you got to the point of producing the sound perfectly.
Practice lists of words that start with "w." Most of the question words, as well as with, was, well... start with the sound, and they are very common words. Make up sentences you would say, and practice them: "When is the wedding?"; "What's up?" Practice "w" words you use frequently at work. Practice using them in sentences. Master them. Then use them with real people in real situations!
That is how the sound will become habituated into your everyday speech.
You really produce the "w" sound all the time, but maybe don't realize it. When you link a word that ends in "oo" as in "who" or "oh" as in "go," you are making the sound. "Go (w)on!" "Who (w)are you kidding?"
If you confuse "w" with "v," you need to reinforce the differences between those sounds. If your language has "f," all you have to do is vibrate your vocal cords, and you will be making "v." Very different from "w," right!?
Use words with minimal pairs at first (wet/vet, wine/vine...), and then it's practice, practice, practice...