When setting up a reed try to get a minimal amount of leakage when it is choked. Any extreme arcing of the reed will interfere with choking the reed because the reed will never close the slot off properly.
In order to develop a good control of the blow reed it is wise to practice choking an isolated reed.
Open up a harmonica and block the draw reed of (e.g. by putting a finger over its slot). Play the blow reed and gently bend it down, if the gap is small enough you will soon reach the point at which the reed chokes.
Bending down the note is done from the H spot at the back of the tongue, not by using the tip of the tongue. The tip of the tongue should remain relaxed, as should the lips and cheeks.
Once you get the reed choked, slowly increase the pressure at which you are blowing and try to keep the reed choked as long as possible.
|Choke the isolated blow reed|