Having limited time to practice guitar is not the main reason why you aren't making much progress. Here are the real reasons why guitarists with limited time struggle to get better:
1. Not Even Trying Due To Self-Sabotaging Beliefs
Many guitar players don't feel like they have enough practice time to become a good player. They think: "You have to practice a lot to become good, but I don't have enough time to practice so there is no point in even trying." Unfortunately, this causes many guitarists to never make any progress, make very slow progress or quit altogether.
Fact: getting better on guitar is about quality over quantity. Great guitarists focus on getting the most from every second of their practice time, rather than practicing as much as possible. It's true that some guitar players practice many hours every day with the goal of getting better. However, this doesn't mean it works for them. When you focus on doing the best you can with the time you have, you quickly begin seeing results like never before. Work together with a guitar teacher to learn how to practice efficiently with your time and get the most out of your efforts.
2. Not Practicing As Effectively As Possible
No matter how much time you have to practice, you get better results when you practice effectively. Many guitarists do not understand how to practice effectively, fill their practice time with mindless noodling and/or practice in an unorganized manner. When your guitar practice is effective and efficient, you make progress no matter how much time you have. Practicing in this manner for just 20 minutes a day easily gets better results than what most guitarists get practicing several hours every day.
Make your practice as effective as possible by finding and working with an experienced guitar teacher who will create a custom lessons strategy for you.
3. They Don't Practice Away From Guitar
A lot can be done away from your guitar to improve your musical skills. Many guitarists don't realize this and miss out on a huge opportunity to improve. Practicing away from your guitar increases the amount of practice time you have and makes your time with the guitar more efficient. This helps you make faster progress. A few examples of things you can work on away from your instrument include: learning music theory, improving fretboard memorization/visualization or songwriting.