My students have access to all my principles on how to play the guitar like a master, these are just a few: 

Place your fingertips close to the next fret. 

This will make you exert much less pressure on the string and it will also dramatically improve your accuracy. Like the old phrase says: Aim for the moon, even If you miss it, you'll land among the stars. If you miss that specific location on the fretboard, that means you'll still be likely to fret the note, just not with as soft of a pressure. 

Practice with your eyes closed every once in a while. 

Visual cues will only take you so far, the real secret is in your sense of touch. It is all about how well you know how to give each tiny spot in your body and fingers the pleasure they crave for. Playing the guitar at the highest level is ultimately a kinesthetic activity. You know the address of every part of your body and how pleasure works. When you close your eyes, you enter that world. 

Record yourself.

Take note of the areas you need to improve and also the areas you are doing well. Work on the 1st and “exaggerate” the 2nd; meaning, cover your weak spots, but be a master of what you're really good at. And more importantly, use it as a tool to get better, not to put yourself down. 

Know your fingertips like you know your native language. 

Your fingertips are made up of many tiny segments, like onion layers. When you press a guitar string, you're primarily pressing against one of these segments because the string is round. Here's the surprising fact: there's only ONE segment that will give you the most pleasure when you touch a string! That will be the segment where the note FEELS the best! What most people don't know is that this ONE targeted segment is not always the same; it keeps changing for each specific note within a musical passage. These target segments change as the passage progresses. As a general rule, you should aim for the lowest part of your fingertips for the 6th string and at the very tip for the 1st when playing these two notes simultaneously. As the notes change, so does the sweet spot. Explore the possibilities! 

Aim for comfort and the rest will take care of itself. 

Ask yourself repeatedly, how can my fingers feel pleasure while I practice this passage? Your brain will not give you a straight answer, instead, it will relax your hands for you and give you that pleasure you are looking for AS LONG AS if you keep asking the same question repeatedly over and over again inside your head. Comfort will make you play better, for longer and faster. THAT is the addictive component to your practicing!

Consistency beats quantity every time.

It is exponentially better to practice every day for 15 minutes than for 1 hour and 45 minutes once a week. Consistency is not a perk; it is a necessity! Organize yourself, get a piece of paper, write down the days of the week on top, and the amount of time on the side. Enter how much time you are practicing every day, and be proud of yourself at the end of the week. You can only skip one day a week, but don't pre-determine it. Life happens, and you can use that day to take a break. We are only free when we do what we don't want to do because if we only did what we wanted to do, we would be slaves of our own desires. Free yourself!

Practice focusing on one finger per repetition. 

Start thinking about your index finger, on the next repetition think about the middle, on the following the ring, then pinky. Do the same for the other hand. The goal is to observe what each one of them does and relax them when not in use.