The environment you choose for practicing is very important. If you put some thought into it, you can make practicing more enjoyable and more productive.
Setting Up Your Practice Environment
Make sure everything around you is comfortable. You don't want anything to distract you.
Make sure everything is in arm's reach so you don't have to go searching for anything mid-practice. You might be sure to have a glass of water handy, too. If you get up mid-practice, there's a chance you might stop practicing early!
You need a quiet spot with good lighting. If you plan to sit, find a comfortable chair with no arms to get in the way. Don't sit on the edge of a bed or anywhere awkward. You want to practice with good posture.
Make sure you have a music stand to hold your study materials where you can see them easily. You shouldn't be twisting your body or craning your neck when you practice.
Make sure the temperature is comfortable. According to research, cooler temperatures relax you and stimulate your creativity. Warmer temperatures arouse you and help your memory.
Keep plenty of pencil and paper on hand in case you want to make notes or write some music down.
You'll want a CD player, MP3 player and/or computer nearby for playing songs. And, you might want a cheap recorder to record and listen to your playing.
A Dedicated Practice Area
Something I highly recommend is creating an exclusive practice place. If possible, find a place where the only thing you ever do there is practice. Don't allow anything but practice to happen in that spot. That way as soon as you sit in your practice area, your mind will go into practice mode. After a while, all you need to do to motivate yourself to practice is force yourself to sit in your practice area. It really works.
If you can't find an entire spot, you can try dedicating just a chair instead. Sit in your "practice chair" only when you practice. Never do anything else in that chair. Really anything could be used to trigger your practice mode like this. I know it sounds silly, but you could have a practice shirt or hat. Or, maybe you practice only after having a glass of orange juice. Be creative. Do something consistent to get you into the practice groove.