Practice and playing guitar should be fun and challenging for newbie or guitar master. Practice should be done with specific goals in mind. I know tons of guitarists who think they are practicing but what they are really doing is just playing.
Playing is important too but practice is something different. What you practice should come out in your playing. If it doesn't, you're not practicing efficiently. Before you sit down to practice, make sure you know what goals you are trying to reach by practicing, short term and long. It may even help to keep a log of your practice sessions. When, how long you practiced, what specifically you practiced and why you practiced it. The goal must come before the process is determined.
Continuance
Just like going to the gym, the important thing is to practice just about every day. Four hours today and nothing else for a week will amount to close to nothing. If you can only stand practicing an hour or so, that's fine, just as long as it is almost every day. Let it become a habit.
Vision
Remember the dreaded F chord? You almost gave up didn't you? Me too. After you got it under your fingers, it was smooth sailing for a while until the next hurdle came up. More so than any other instrument, the guitar will challenge you this way. That is why it is important to set realistic goals with specific time limits for yourself. Always remember, nothing can be learned in an hour or so. The goals you set should be for weeks or months. Some of the things that I am currently practicing will take me a year to get together. Don't get discouraged; anything worth learning will take time.
Balance
The way you practice should change with time. I've been playing for twenty somewhat years, so what I practice these days, is completely different than what I worked on my first few years. I know all my scales and have enough technique that I don't need to work on those very much. I usually work on improvising over really hard chord changes.
Stuff like John Coltrane's 1 "Giant Steps" or a Wayne Shorter song. I may sequence my own chord changes and try playing over them. I also find that working on the tunes for the gigs I do often turn into a good learning experience. For that reason I never turn down gigs that I know are going to be a real pain in the butt to get the tunes together for. Keep practice and you'll be a good guitar player.
