First of all, what is the difference between playing and practicing? Playing means that you are playing songs that you have already worked out. You are just keeping them in your memory, or maybe you just really like a particular song, or you are just having fun. It's more like what you do in a jam session.
What is your goal? How long and often should you practice? First of all, make sure that your goal is reasonable. It might be reasonable to play at least one scale every day, but not reasonable to play for one hour every day. And with practice, how OFTEN you practice goes farther than how LONG you practice. Playing for 4 hours every weekend is great, but if you can spread that out over the entire week, you'll progress more and faster.
Make sure your goal is not just to practice for a set amount of time. That's like saying you are going to sweep the floor for 10 minutes with no mention of the fact that the real goal in sweeping the floor is to get it clean. Maybe your first goal is to learn how to play Part A of a song. You know what you want to accomplish (learn Part A), but you still need to decide how you will accomplish it. At this point, you may decide that you will practice Part A for 15 minutes, three days a week until you can play it. This gives you the goal of WHAT you want to accomplish along with the goal of HOW you will go about accomplishing it. It does not set a time limit on how quickly you have to learn the song because everyone learns at a difference pace.
If you have a time limit, for instance you have to play a song at a wedding in one month, then you will have to set different goals. Your goal may be to memorize two lines of the song each day until you have the whole song memorized. You will practice for however long it takes to get those two lines down each day you practice. Then you still have to leave time to put the whole song together and get it polished before your performance.
Practice SMARTER: Another great goal would be to practice for at least 10 minutes on days that you have your lesson (after the lesson when you get home). It REALLY helps you to be able to remember what you did during your lesson, which will help you in all your practice sessions all week. If you don't take lessons, remember this technique when someone shows you how to do something. If you're out at a festival or jam and you learn something new, make sure to go over it again as soon as possible so that you don't forget it.
Practice what NEEDS practice. If you can't play the last line of a song, don't keep going back to the beginning to play it all the way through. Practice the last line. I know this might seem like something everyone should know, but as a teacher I see this happen all the time. Especially with beginning students. Many beginning students tell me that they can't start in the middle of the song. You have to learn how to do this -- even if it means getting your tab or music out to help you do it. If you know you have a trouble spot in a song, start with the trouble spot before you play the whole song. That will increase your chances of playing the song correctly the first time through. If you always start at the beginning of the song, you will waste practice time on the part you already know. For instance, if you know Part A of a song, start with Part B, and play Part B several times before you put the whole song together. Since you started learning Part A first, you will have played it more times than Part B. (Commonsense, I know, but most people don't think about this.) In order for Part B to "catch up" to Part A, you need to play it twice as much.
Practice with others. Maybe your goal needs to be to practice with other people. Practicing with others is one of the best ways to get better faster. If you haven't tried it, let me warn you that it's hard for most people. It's worth the effort! Many times when people first start attending jam sessions, they tell me they feel lost and frustrated. Don't let this stop you. Keep trying until you can do it. You may play better in your living room, but eventually you will be able to "carry that living room feeling" with you to the jam.
If you don't have other people to practice with, then practice with a recording. If you can't keep up, use a program that will slow the song down. Windows Media Player has this feature built in as long as the song is saved on your hard drive. If you have a CD you want to play with, save it to your hard drive, or purchase a Guitar Trainer (a CD player that allows you to slow down and speed up the CD). If you can't stay with the recording, keep trying until you can. Try five or six times right in a row before you go on to something else. Eventually, you will get it! You may have to practice the song 10 times by yourself first, then try the recording again after you have worked out the spots you had trouble with.
Try television practice. What??? This is one of my biggies, especially for kids who try to tell me they don't have time. I ask them if they watch any television. The answer is almost always yes. I tell them to take their instrument with them to where they watch tv, then play it during the commercials. If you play during the commercials of a 30 minute program, you have probably practiced about 10-15 minutes. Not too bad if you consider the alternative was to not practice at all. Reminder: I'm not saying do ALL your practice this way!!!! I personally will use this method while watching the news if I am trying to memorize something. I have 5 minutes or so to play through a phrase or portion of a song, then I watch some news, then I see if I can remember what I memorized during the last commercial break.
This certainly isn't all-inclusive, but it is a start to getting you on the right track. I'll address some specific practicing techniques in another blog, but for now, you can start setting and accomplishing those goals!