Hey & welcome to GT!

Originally Posted by: ken.needham

When I take my finger off the a string after playing it, there is a "residual" sound as I move to the next string. What causes this? Is it the way I'm taking my finger off?

Effective muting technique will fix this. Use your picking/strumming hand palm to mute any & all strings that you don't want to ring. Use your fretting hand to mute also. When you are done fretting a string don't pull your fingers away from the strings. Continue to make slight contact with the strings. Just release enough pressure to stop the string from ringing. Keep enough pressure on the strings to stop them from making unwanted sound.

Also, remember if you are a beginner, then you are doing great just to get some notes fretted, picked & sounding good! Muting is another layer of technique to add in once you get the basics mechanics of fretting notes. Guitar is a constant process of refinement.

I cover basic right & left hand technique involving muting in this series of lessons.

https://www.guitartricks.com/lesson.php?input=10657&s_id=359

This tutorial covers fretting & strumming hand muting. In particular have a look at the beginner level tips.

https://www.guitartricks.com/tutorial.php?input=2281

Hope this helps. Please ask more if necessary & best of success!