Both of these sounds ( V & W ) are articulated using the lips, and both sounds are voiced, meaning that the vocal cords vibrate during the sound.
The ‘W’ Sound
When you create the w sound (w sound), your lips are brought together enough to cause a vibration when the air passes through between them. Your lips don’t need to be in a really tight circle, just enough to make them tickle a little bit equally on the top and bottom lip. The key is that the lips are both vibrating the same amount.
The ‘V’ Sound
The v sound is voiced (the vocal cords vibrate during its production).
To create the v sound, the jaw is held nearly closed. The upper backside of the bottom lip is pressed very lightly into the bottom of the top teeth. Air is pushed out the mouth between the top teeth and the upper backside of the bottom lip. This sound is a continuous consonant, meaning that it should be capable of being produced for a few seconds with even and smooth pronunciation for the entire duration.
The lips are kept mostly relaxed during the v sound. A common error ESL/ELL students make is overproducing this sound by curling the bottom lip under the top teeth. This creates problems when linking to and from the v sound.