This tip was given to me by an outstanding flute private teacher. Works for brass and wws:

Step 1-Begin with first group of 4 sixteenth notes and include the 5th note in the run. Play long, short, long, short, long slowly and accurately.

Step 2-gradually increase speed repeating the same 5 long short long short long.

Step 3-Using same 5 notes, play them short, long, short, long, short. Repeat step 2 gradually increasing speed.

Step 4-play the 5 notes as written slowly and gradually increase speed.

Step 5-Focus on notes 5-9 and repeat steps 1-4.

If you have 8 sixteenths:

Step 6-play notes 1-9 ala step 1 and 2.

Step 7-play notes 1-9 ala step 3 and 4.