@sydyous
The pinky finger is almost a nightmare for every guitarist. I follow certain principles of guitar playing that others do not follow. Most importantly on finger position. I play with the intended finger (the pinky) instead of using a slide to hit the not with the ring finger. It is difficult until you practice it. So how do you go about building strength and dexterity in the pinky?
First and foremost you stretch. I found a video that has some of the stretchings that I do, as well as a couple more.
Then I have an exercise pattern that I follow to help with stretching and playing notes cleanly. In the tabs I post below please read the instructions at the bottom of the page for clarity. For example position 5 on the neck is played with the pointer finger always. I have for you the 2nd finger, 3rd finger, and pinky finger exercises.
Do stretching and then follow the exercise as a warm-up routine. Pay special attention to the pinky finger as it will most likely be the hardest to keep a clean sound.
On top of that, all the exercises are on the 1st string of the guitar. When you get comfortable with the first string, move to the 2nd string. Slowly work your way up the strings. The reason for this is as you will find, your thumb position will change on the back of the guitar. The 6th string on an acoustic guitar I can play but not with any real strength in my pinky.
Different styles of guitar have different fret positioning, different neck widths, as well as other features. If you need to adjust to a more comfortable fret to play then do so. Remember that it is not supposed to be easy, you are forcing your fingers to stretch and gain strength.
Let me know how this works for you.