It is important to exercise the tongue and to place it correctly behind the teethaccording to the syllable being formed and the pitch of the note.
 

a.    Practice articulating rhythm patterns of notes in time and with a strong pulse. Play this example while keeping a constant count of 4 beats in each bar.  

b.    Play this exercise over the whole trumpet range. Note that for the higher register the tip of the tongue will be striking behind the top teeth. For the lower register the tongue will strike the lower part of the top teeth.

c.    Articulation and finger co-ordination must also be practiced. Do this over scales or scale exercises.

d.    Double and Triple tonguing need to be exercised at this point also.  Think about the way the tongue travels backwards and forwards to get the smoothest attack. (1) Learning to Double Tongue - Start by saying the syllable Ta Ka very slowly. Then practice saying it without moving the jaw or any mouth muscles. Only the tongue moves. Then continue doing this as you slowly close your mouth and get into an 'embouchure' shape. Now try doing while buzzing. Keep practicing this to a beat and gradually increase the tempo. Eventually place the mouthpiece on the buzz and practice getting a clean attack on both the Ta and Ka.

        
Arban's Method of Double and Triple Tonguing is excellent although I prefer to practice the TuKuTu as a slower triplet before speeding up to the faster TuTuKu

REST BETWEEN EXERCISES BEFORE GOING ON TO PLAY YOUR  SCALES.