For technical work use a metronome. The importance of a metronome can't be stressed enough—it's the most valuable tool you have. Not only will it allow you to gradually increase the difficulty of your practice routines, it will also help you play in time better. Any musician will tell you that being able to keep great time, not rushing or dragging, is one of the most important traits you can have.

You also should find a quiet and comfortable space to practice. Turn your phone off; log off your online service. Try to get a solid hour with no distractions. Sit in a comfortable chair. Make a nice space for yourself. You should be comfortable there—mood lighting helps too.

No matter what you practice, you need to start slowly and work up the speed. Trying to play too fast just reinforces mistakes. If you have a difficult passage, slow it down and figure out what parts give you problems. Once you identify the trouble sections, work on those separately. It's quite normal for musicians to work on small chunks of music and later work on the whole piece. If you have a trouble spot, drill it until you get it right.

And finally, keep a logbook or a practice journal, and keep track of what you did and how long you did it.