As a beginner, I find my fingers going everywhere but the places I want them! This is especially true when I'm attempting scales/licks that use my 4th finger a lot or requires quick interchanging between my 2 and 3rd finger.
What is the best way to work on my fret hand finger independence?
I think the key is muscle memory. The only way to improve this is by specific repetitive movements. In your question you state: "quick interchanging between my 2 and 3rd finger." Presumably there is a song you are working on that requires this, so the part you are having trouble with, do that move over and over again until you no longer have a problem doing it. After a while, "rewind" a little and play the lead up to that bit and then play a little beyond it, repeating this on a loop.
The key is to do this with every movement you find yourself having any difficulty with. Identify it, repeat it, get comfortable with it.
Don't worry! Every new guitar player goes through this.
The key is to not disregard the 3rd and 4th finger and use them a lot especially when practicing dexterity exercises. Your thumb is close to your 1st and 2nd finger, so that makes those finger more capable of playing these exercises.
Don't disregard the 3rd and 4th finger, push through on your dexterity exercises and this will come to you.
A systematic set of exercises can help. Try to practice every possible move in isolation. Do these at each fret position to get comfortable all over the neck.
Index-Ring, Middle Pinky.
$6 1 3 $5 1 3 $4 1 3 $3 1 3 $2 1 3 $1 1 3 2 4 $2 2 4 $3 2 4 $4 2 4 $5 2 4 $6 2 4
The "spider" (can be mirrored 4 ways):
$6 1 2 $5 1 $6 3 $5 2 $4 1 $6 4 $5 3 $4 2 $3 1 $5 4 $4 3 $3 2 $2 1 $4 4 $3 3 $2 2 $1 1 $3 4 $2 3 $1 2 $2 4 $1 3 4
Buddy Holly riff (do it with Index-Middle/Index-Pinky and Index-Middle/Index-Ring).
$5.1.$4.3 $5.1.$4.3 $5.1.$4.5 $5.1.$4.3 $5.1.$4.3 $5.1.$4.3 $5.1.$4.5 $5.1.$4.3
Drop D Power Chord Scales. Play with Index Barre, Middle Barre, Pinky Barre, and shift up to higher positions. You want to be able to go up and down each string as well as across all 6.
$6.0.$5.0.$4.0 $6.2.$5.2.$4.2 $6.3.$5.3.$4.3 $6.5.$5.5.$4.5 $6.6.$5.6.$4.6 $6.7.$5.7.$4.7
Search for "The Steve Vai 10 Hour Workout" for a really excellent set of exercises.
You need to practice slowly and with concentration. It is not about training your muscles it is about training your brain. You are learning how to move your hand in ways that you've (probably) never done before. You need to go through the motions carefuly and slowly, consciously monitoring how you are moving your fingers, scanning for tension or strain in your hand, and trying to remain relaxed and fluid. Doing this for a relatively short period (5-10 mintues, anything longer and it is hard to keep the high level of concentration up) every day over weeks to months will improve you ability to smoothly and independently move your fingers.
For finger independence in general. A good exercice is the following. Play frets 1, 2, 3 and 4 ascending on each string (one finger per fret, so i on 1, m on 2, a on 3 and x on 4) from the sixth string to the 1st. Only play these four notes per string, the point isn't to play a chromatic scale, it's just for left hand practice. The trick is this: Once you've played the 4 notes on the sixth string, to play the next note (first fret of the 5th string), only move the finger you need to move (index finger) and keep the others down in the position of the last note they played. For the next note (2nd fret of the 5th string) move your middle finger but not the other fingers (so a and x are still pushing down on the 3rd and 4th frets of the 6th string and i is pushing down on the 1st fret of the 5th string). Etc. Etc. You can also follow this pattern descending and can make a loop out of it. The idea is to only move one finger at a time, while the others are pressed down on the neck. You will probably feel some tension in your fingers as you're basically working against the sympathetic nature of the other muscles (for me, the hardest is the ring finger). I wouldn't overdo it with this exercice as it's really strenuous on the hand but it will do wonders as far as finger independence is concerned.
For finger independence on chords. A practical way of getting your fingers to remember where to go is to put your fingers in the position of the desired chord, push down (not even necessary to play the chord as you're only working on the fretting hand), then release, completely open your hand (while keeping your thumb on the neck), then place your fingers back in the chord position, release, open your hand, etc. etc. Repeat until your fingers know where to go on their own. It's a good way to stimulate muscle memory.
