You can play just about anything you want to at some tempo. It is important to practice as slowly as necessary to play something consistently without error. This may be 1/2 speed, 1/4 speed or slower. If the tempo is too slow to sustain your breath long enough on a wind instrument, simply finger the notes and hear them in your head. Surprisingly, once something is learned, speed can often be increased rapidly and you don't have to move upward through every marking on the metronome. However, if something is played too fast with errors, those errors may become "learned" and have to be unlearned and corrected later!
2. With a metronome
A metronome is an essential tool for a musician. Some things it can help with:
It will show any tendency to rush or fall behind the tempo and/or to play with unsteady time.
It can be an excellent record of progress. As days or weeks go by, evidence of progress can be seen as the tempo increases. Generally, the ability to play something faster indicates more security with the particular skill.
It can give different perspectives of time by orienting the click on different beats of the measure. For example, in 4/4 time, practice with the click on every beat, just on 1 and 3, just on 2 and 4, just on 1 or some other beat of the measure. What is easy to play in time one way may be difficult another way.
Once you become comfortable with it, a metronome can become a "security blanket" because its time is steady and you can trust it. Therefore, it is also important to practice without the metronome and to feel the pulse just as strongly in your mind as if it were being played.
3. For perfection
As imperfect human beings, we must strive for perfection. Part of this is gaining more consistency or the ability to play something correctly every time! We will never be perfect but it is essential to know what it feels like to play certain things perfectly. Towards this end, there is nothing like sheer repetition and that implies playing something as many times as are necessary to achieve perfection! Also, once something is learned it is important to trust in the fact that you have learned it and never doubt that you can do it!
4. With a daily routine
Naturally, it would be good to spend as many hours practicing as possible and that is definitely necessary at one or more points in a musician's growth. However, as important or even more important is having a regular routine that is adhered to. Practicing an hour a day without fail would be far preferable to practicing seven hours one day and none on the other six. Also, a routine must involve an amount of time and a schedule that is realistic and can be fulfilled. Your routine might involve one or two hours a day in one block of time. Or it might be divided up in two or three parts spread throughout the day. You should budget your time and discipline yourself to stick with that schedule. If you have alloted ten minutes to something, when that time is up you should move on. It is important to not neglect portions of your routine that are important to you even if it means cutting short the time you spend on something. On occasion, when inspired and presented with a large block of time, you may wish to spend several hours and find that time very productive. The other side of that coin is the time when you probably should have stayed in bed and will simply not accomplish much in that session. You should be careful not to overuse this rationale though!
5. Something in all keys
Music is written and played in all major and minor keys. Therefore, your long-term goal should be to be able to play whatever you want in any key. On a daily basis, part of your routine should involve playing things like scales, chords, piano voicings, jazz cliches, II-V-I patterns, etc. in all keys. You are probably relatively secure with half or more of the keys so concentrate on those keys that are intimidating to you. Playing some things may be extremely awkward feeling in some keys at first. However, ultimately it is a matter of familiarity and the more you play something the easier it will become. Remember to set your metronome to a tempo at which you can play something perfectly in all keys and proceed from that point.
6. Several things in one key
Another good thing to do is to take a "key du jour" (key of the day) or possibly spend a week or more and play everything you know or want to know in that key. This will help your awareness of things like function and how shapes move through the scale or key. Try to understand the nature of a chord progression in the key of "X" so that you can reproduce it in any key. Look at a melodic cliche or pattern and see where it starts in the scale or chord and how it moves, i.e. 3-1-3-5-7-9-8-7-6-5. Analyze chord voicings so that you can reproduce them in other keys. Play all of the jazz scales from the same note and observe their similarities and differences.
7. Etudes, technical studies
For any instrument, there are traditional etudes and technical studies that deal with important issues of playing the instrument. Many jazz players find it worthwhile to incorporate some of these into their practice routines. Studying the instrument with a good teacher can help you become acquainted with some of the best things to practice.
8. Classical literature
Playing the classical literature can teach you a great deal about harmony, melody, articulation or phrasing, rhythm or time and musical interpretation involving shading and dynamics. Also, one learns a lot about the sound of the instrument and good tone production even though a concept quite different from jazz may be required.
9. Chords and scales -
All musical motion is either stepwise through some scale or in leaps through some chordal structure. So, to some extent, if you learn all your chords and scales, you can play music! This is, of course, an oversimplification but holds a lot of truth. Therefore, it is a priority to be able to play all your chords and scales in all keys.
10. Jazz patterns, clichés
There are many familiar "words" in the jazz vocabulary which actually allow us to turn on the radio or put on a recording and to be able to recognize it as jazz. Many cliches are played by all jazz players and some musicians have cliches that make it possible to recognize them individually. We can glean these cliches from recordings or from published books of transcribed solos. Ultimately, each of us chooses the patterns and chiches of our liking and, in that way, we become our own players. Favorite chiches should be a part of daily practice because they give us more to draw on when we have to improvise a solo at sight over an unfamiliar chord progression.
11. Voicings, chord progressions
The piano is a basic tool for all musicians and should be used to internalize typical idiomatic jazz sounds. A horn player can only arppegiate a chord one note at a time and must use the piano to get the complete picture of the various harmonic colors. Most good horn players can sit down at the piano and play really good sounding jazz voicings. This has helped them to hear not only the harmony but guide tone motion and resolutions as chords change.
12. Learning tunes by ear
Books which contain hundreds of tunes are a valuable resource but should be used like a dictionary. In other words, when we're not sure of a melody note or chord change, we can look it up. Many young musicians are far too dependent on fake books and never really learn tunes well. Try learning the melody and chord progression to a tune from a recording by a good singer or a player who is faithful to the subtle details of the melody. Because of the lyrics, a singer is generally going to sing all of the melody notes as they normally appear. However, some singers may stylize the melody so drastically that it is hardly recognizable. The same is true of an instrumentalist who may want to only allude to the melody in an obscure manner. One advantage of learning a tune by ear is that you don't have to memorize it! Once you figure it out, it is learned. And the process does good things for your ability to hear melody and harmony which is an indispensible attribute for a musician!
13. Away from the instrument
It has been said that a musical instrument is a loudspeaker on the soul. Whether or not this is true, it is definitely true that the instrument can not do anything for you. It has to be directed by you, your kinetic system and your inner ear. Since there are many times when it isn't practical to actually play the instrument, it can be useful to practice "thinking" and "visualizing" things we want to learn. Fingering can be practiced without the instrument. Chords and scales can be "played" in your mind and visualized as though they were written on a musical staff. Chords, scales and specific voicings can be sung and this will help form a stronger image of them in your mind. You may find that the next time you go to the instrument, things that you have practiced this way are easier!
14. Day dreaming about playing -
So much concerned with playing this music demands that you have a strong sense of how you want to sound. It may help strengthen your musical conviction to imagine yourself playing with great players and to hear yourself sounding great! Try to imagine specific notes and see them written on the staff as though you were the composer of the composition you hear in your head. Carry the memory of this daydream with you to your next music making session and try to reflect it.