How to master the guitar
This is probably a phrace  you heard many times before but it is certainly a concept that is much easier to obtain than you may think and not at all impossible as it may seem. As important is it to understand it can be a wonderfull experience and an enjoyable process once you find you nitch, the road to mastery

Find your voice
The most important thing in mastering the guitar is becoming completely clear about what it is you want to achieve on the guitar and the awesome thing about this is that once you find it, practicing is not anymore a chore or something you need disccipline to do or force yourself in any way to do, you really have to understand that the mastery in itself is not an end goal but a process. And once you find your nitch it will feel like your on your chosen path and you will not be in a lot of doubt anymore as to what you should do or practice

How  to go from here
I will give you the lowdown on how to do just that, get a piece of paper and write down all the things you find awesome about the guitar and spend some time on this, once you have a list of techniques or styles you love, make sure you arrange them into your top priorities first to last, once that is done take the top five things on your list and write those five things down on a new piece of paper. For every thing you have added on that piece of paper you write down the steps that will take you to each goal

What to practice
So once you are really clear about what you want to master or which goals you have its time to jot down the steps you need to take to get to each of those goals. I want to give you an example so you know what the hey im talking about, let's say I want to master Sweep picking as my top priority, what needs to happen for you to get there ? this is what most people think is stating the obvious, but if this where true everybody would be a master, right ? So ill tell you right now that just sitting down practicing random sweep picking lessons will not do, you have to have a strong mindset to be successfull, and this is not to be confused with discipline 

The winning mindset
Now here's what its all about, the winning mindset, what this is, is not discipline but more a specific way of doing things, a "first thing's first" mentality if you will. The reason I mention this is because I have been teching guitarists for years who claim they practice hours a day and they have nothing to show for it. Once I get to dig a little deeper in their way of practicing its always because they don't do what's neccessary consistantly which is to choose one lesson and practice it consistantly until the goal is reached. So before you dismiss this idea be really honest to yourself, if you have been practicing for a long time and have not yet reached the goals you want, could it be because you have not been consistant enough and you may have looked for easier outcomes like searching for just the right lesson or lick that will perfect your playing ? only you can tell but for your own sake be honest and get back on the winning track and stop wasting your time