Not all guitar practice is equal. Optimising your practice can make a big difference especially over the long term. Developing the habit of optimising will at first, feel like an effort. Like most habits it will take time but stick with it. It may also go against your natural instincts and urges. Optimising can also feel tedious and downright boring. While optimisation is not exactly exciting the results will be well worth it. I am going to give some examples of how I optimise practice but note, there are an infinite numbers of ways so feel free to explore.

1. Zoom in. Any skill is a series of actions. Each action will require a varying amounts of repetition to master. Lets say that a certain skill involved 10 distinct actions or steps. If you practice those 10 actions in sequence (which is what most people do), you will each get roughly the same amount of repetitions. If you instead focus on the actions independently you will be able to work on those that need it and less on those that do not. This will help you to learn the skill quicker because overall you will need less repetitions.
2. Start slow. What most guitarists do when learning something new is begin at a moderate tempo. The speed which they think they can play the exercise or song. The speed is almost always too fast. After several unsuccessful attempts they slow it down slightly. This process is repeated until they either lose interest or persist and reach a tempo they can begin to correctly learn the song or exercise. As you may have concluded this is not just a substantial waste of time but worse, its counterproductive. Now you have to undo the bad habits develop at the faster tempo. Slowing right down from the start allows you to see where your weaknesses are and correct them early. Even when you feel something looks easy get into the habit of starting slow. Taking this approach will minimise errors when learning and will save time which in turn speeds up the learning process.
3. Video yourself. You would be hard pressed to find a sport today that doesn’t use video to improve performance. Recording a player in action allows coaches and sports players to review performance after the fact. As the guitar student you are in the moment. Your brain is trying process everything from fretboard finger placement to picking hand action to the music itself. Its simply not possible to analyse everything in the moment. Watching a video replay can be hugely enlightening giving you clues as to weaknesses in your playing.
4. Create sessions. The most productive practice for me personally comes when I break down my practice into 10 minute sessions. This is because it maximises concentration. I know after 10 mins my focus starts to drift and the quality of my practice declines. Breaking my practice down into skill sessions (e.g. picking, chords, arpeggios, scales, rhythm, reading & aural) plus songs allows me to drill down and focus on one small element. Detailing if you will. Every 10 minutes I will switch to a different skill or song.
5. Mentally prepare. The term ‘deliberate practice’ is used to make the distinction between mindless practice and mindful practice. We are all guilty of mindless practice where we might play a scale 10 times on autopilot. Improvement is unlikely in this mental state. Putting yourself in the right mental state before starting your practice will increase the chances of your practice being deliberate. Try to create a list of what stimuli puts you in the right mental state for practice.