So - you've been practicing diligently, wearing out the metronome, and broken an incalculable number of strings, but you still feel as if everyone you know is progressing faster than you? Or, you are trying harder and harder every day, seeing little to no improvement?

You've officially hit the "Wall," that seemingly insurmountable barrier that just looms over every practice session, casting it's shadow over every note. Have no fear, fellow ax-grinder! I've dealt with this problem both in my own play and with students, and as such - I've got you covered. Although there are many articles available on how to get out of this musical rut, many are vague and redundant. Here are eight very simple Wall-jumping steps that will get you to new levels in your quest for shred perfection.
Set Up Your Instrument Properly!
This might sound self-evident, but more often than not, I see players (even those with enough experience that they should know better) buy a new guitar, put on some fresh strings, and call it "good enough." Before doing anything else to improve your play, have your guitar set up by a professional, for a level action and proper intonation. It could be that you find a song that has always sounded "off" comes out just right after a proper setup. Not to mention, the ease of play, smoothness of bending, and better tone will influence the way you feel while you play, and lead to overall better practice. If you are so inclined, it is well worth the time to learn how to set up your instrument on your own - the money and frustration you will save yourself over time will justify the price of the educational materials.

Listen Objectively to Your Own Playing
So many players can seemingly critique others' play with relative ease, yet when it comes to their own tone searching, they seem to have on blinders. Of course, it's really difficult to separate what you think you're playing from what you're actually playing. Need an example? Go to any crowded guitar store and head for the demo amplifiers; you're likely to see at least two or three players who believe they sound like Hendrix or Santana, but sound more like some poor creature in need of immediate medical attention. A good fix for this situation is to record yourself, playing as you normally do, with no studio program trickery or multi-tracking.
The idea here is not to get the perfect CD-ready mix, but to become your own audience and hear yourself as others do. It's like looking into an audio mirror, of sorts. When listening to your recording, really try to listen with your ears rather than your mind (this is a lot easier to say than to actually do).
Identify the Strengths and Weaknesses in Your Plan
If you've completed the previous step, you've likely seen your play realistically; warts and all. The point of doing so was not to make you hang your head in shame, but to progress to this step. You see, the problem doesn't lie with how hard you're trying, but in the value of the time you're putting in, and the direction from which you're approaching your goals. So many players, whether consciously or not, spend almost all of their total practice time playing the things they already do well. What makes this a problem is that by doing this, you never get to improve upon your weaknesses and build upon those strong points - which is the goal of practicing in the first place! So, returning to your realistic self-assessment, pick out the bad spots.
This is what you want to focus the majority of your practice time on! If your arpeggios are sounding sloppy, for example, then slow down your metronome and work on the technique until your playing smooths out. If your pinch harmonics are weak and lifeless, crank up that gain and start focusing on that until you get 'em squealing. The idea is to increase your proficiency overall, so that your play will have consistency. If you can play the best tremolo picking in the world, but your sweeps are bad and your bends never hit the mark, then your overall play will be judged as bad - not good with a few weak spots (listeners are rarely too forgiving of bad play).
Branch Out
Now that you've started honing your chops, you're hopefully feeling a little better about yourself (rightfully so), and thinking that maybe you really can be a professional. Now, however, we have to start developing a well-rounded approach to guitar. It never ceases to amaze me how often "musicians" refuse to explore other styles of music than their preferred style. Whether it be a classical purist who shuns metal as "dreadful" or a rocker who just can't bring himself to try some "chicken-picking" country licks, to avoid learning different musical approaches is to place a limitation on not only your guitar playing, but your level of overall musicianship.