The embouchure is as personal as the flutist: a combination of physiology and training are the determining factors in developing the muscles used in flute playing. It helps to keep a magic 'space bubble' between the top lips and the teeth: anchor the top lip slightly on the canine teeth to allow a flexible, firm, but not overly tight top lip. The lower lip is the cushion over which the air flows, and the angle of both lips will change depending on the octave you need to execute. Above all, don't allow the corners to become upturned, in a smile, or overly tight. Use a mirror on your music stand to check in visually. Balance both sides of the mouth, even if the aperture is located slightly off of center. Harmonics and whistle tones are wonderful for developing correct embouchure habits.
Working on Finger Technique
If at first you don't succeed on a technical passage, try something different! Many students revert to practicing slowly when they need to fix a finger glitch, but just practicing slowly might not necessarily be the fix. Try practicing from right to left (the passage backwards), and try breaking up the passage into several smaller chunks of notes. Work these smaller bits with different rhythms (dotted eighth and sixteenth notes, then reverse that) as well as triplet rhythms. Make sure to practice the 'seams' of the problem, getting into the trouble spot smoothly as well as getting past it. Vary the articulation. Switch up the octaves. Try a practice chain: play the last 4 notes in the passage perfectly, and add a note onto the chain (last 5 notes, last 6, etc) until you complete the chain. Repeat each small chain perfectly 4 times. Now go practice!
Breathing It always comes down to the basics: mastery of breathing is a cornerstone of flute artistry. When we breathe it's important to stay open enough to allow the air to enter the lungs completely. Think of adding width to the back and filling up all the way around the body, or think of diagonal action in your back. Try not to tense up the shoulders or raise them when inhaling.The sternum can lift a bit when you take your deepest breaths. Keep your throat open and free on the inhale as well, and keep the belly soft so that it can expand a bit as well. These tips should help you get enough air into the body to use for even the longest phrases.
When working on developing speed in double and triple tonguing, keep in mind that the tongue needs to be as relaxed as possible..and since the tongue is one of the stronger muscles in our body, it takes extra awareness to keep the tongue light and precise. Remember that the main articulation syllable for single tonguing, TU, comes from the French, and not our English word Too, which puts the tongue in a very different position. The syllables DE GE work best for double tonguing quickly. Experiment and work on articulating the same pitches before working on running double tonguing, or different pitches for each tongue stroke, of course always with the metronome.
Technique and Musicality
Remember that each passage you practice, whether it be scales, a passage from repertory, anything that you play has to have musical meaning and context! Many times we become hung up on the 'correctness' of a passage instead of working through it to fire the soul and communicate the composer's musical intentions. Keep searching for the meaning behind the technical passage to bring your practice more to life.
Practice Passionately! When you are practicing, make sure to devote your attention to ALL details and not just go thru the motions. Many mistakes can be avoided all together by really tuning in: Active listening (what is actually being produced in sound) is as important as Mental listening (projecting the ideas you want thru the music). But what never works is allowing distracting internal dialogue to occur when working..avoid this at all costs! Stay in the moment and stay connected and you will get twice as much done in half the time. Happy Practice!
Check your Alignment! Always double check your alignment! When we put our flutes together, we are in a bit of a hurry at times....You should have a nail polish mark on your headjoint and body tenon to assure that your headjoint is aligned to your personal setting (somewhere close to the center of the embouchure blow hole aligned with the center of the c key on the body of the flute). Also, make sure the the foot joint is aligned with the center of the body keys lining up with the main rod of the foot joint. I have noticed that if my sound feels a bit off some days, I have missed this alignment by a tiny amount...proving that the smallest details add up to quite a bit.
So, take a moment to make sure you are aligned correctly at the headjoint and at the foot joint.