Fourth week
Practice Habits 
Practice every day! There is no one thing better for morale, that will help you “stay with” study, more than the steady advancement that follows from everyday blowing. On the other hand, there is nothing more demoralizing than the sad result of hit-and-miss practice. The lips stiffen and refuse to vibrate, reactions in general slow up, and it takes days of hard work to get back to where you were. 
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Form the habit of routine. If possible, start practice at the same time each day. Keep at it until music time becomes  as regular a part of the day as breakfast, lunch and supper, The beginner would be wise to have three or four sessions of fifteen minutes, rather than one long practice (which would be too much for an undeveloped embouchure)
(Embouchure  training, page 58,Prelude to Brass Playing)