Double-check and make sure everything is clean, your stem, vase, etc.
Use cold water.
Also, make sure that the tinfoil does not touch the shisha.
Finally, you can take your quicklite and break it in half and place each half on different sides of the bowl. Make sure the coals are completely lit first (Light them and leave them on the tray for about 5 minutes, when you come back they should be covered in a gray coating).
Hope this helped