Use a mirror to see difference in lip movement for these sounds. Touch your throat to feel the vibration for these two sounds.
Place your top teeth on your bottom lip. Blow out air while using your voice.
Put your lips together and release them while using your voice.
The "v" sound
The "v" sound
The "b" sound
The "b" sound
NOTE: the "st" sound is a consonant blend. In blended sounds, you pronounce both letters quickly together in one syllable.