Don't fret if you have difficulty scheduling a half-hour daily piano practice into your busy week. Perhaps more important than trying to squeeze in enough practice time is squeezing all that you can out of the time that you do practice. Here are some helpful tips to maximize your time:
Practice in 5 to 10 minute chunks. It's not necessary to cram all your practice into one segment. For years, because of repetitive strain injuries I incurred from my former office job, I practiced in 3 - 5 minute segments throughout the day. The best part about this was that I got to enjoy playing piano all day long! Think of all the opportunities to run to the piano for a few minutes: - While reheating your dinner in the microwave - During TV commercials (they can be 5 minutes long sometimes!) - While waiting for a friend to arrive - In between other household tasks - While waiting for your tea kettle to boil - 5 minutes before or after a meal - A few minutes before bedtime You get the idea ...
Keep a record of your practice time. If you're like me, trying to mentally track how much I've practiced or even what I practiced is overwhelming. While there are some good practice journals that you can purchase, you can also just jot down on a piece of paper (in pencil, so you can easily edit) the items you need to practice - names of pieces (songs) you're learning, scales and other technique - and then just tick them off as you do them. Leave the paper on the piano so it's easy to access. I used tally marks to track my practice - each mark represented a set time (3 minutes, for example). So, I could see, oh, yeah, I already practiced that scale 6 minutes today. I used different coloured pencils for subsequent days to track what I've done and where the holes in my practice are.
Practice your pieces in small segments. A good teacher will help you find the best way of breaking a piece down into manageable chunks. You learn better and faster by isolating and mastering small phrases of music. Sometimes as small as a single measure or beat! Simply playing through the whole piece over and over doesn't hone specific and varied skills that require a concentrated focus. It's like playing baseball but never spending time just on catching the ball, or on throwing techniques etc.
Remember the 3 times in 30 seconds rule! When you can finally play a small section of measures all the way through without stopping, play it 3 times correctly in 30 seconds, and this will help build your long term memory.
Take a break! Sometimes after a concentrated period of practice - say, you've had a good week or two of practice time - you'll find that suddenly, for no seeming reason, you're making lots of mistakes with the pieces you've learned. From my experience, this is usually your brain's way of telling you that you need to take a break so that it can process all that you've learned. Take a few days off, and you will find that when you go back to play, you play better than before you started having the difficulty. In this case, rest is your practice!