Tip #1: don't burn it.
Add as much heat as the dmt can absorb by boiling off. Any more heat will only burn the DMT. Heat the pipe bulb evenly and roll the liquid around the chamber, that increases the surface from which vapour can arise.
Tip #2: be patient and go slow.
Go slow with the flames while you let the vapor chamber fill up with white clouds. I put a cork from a wine bottle in the top hole, and as it doesn't fit very well, I can easily draw air through the pipe with the cork in, but at the same time the cork keeps the vapour inside the pipe. Denting or cutting the cork can be used to optimize the venting behavior of the cork.
Tip #3: take a deep hit.
When the pipe bulb is all white, breathe out deeply and start sucking on the pipe. At first, you'll get pretty thick vapour, keep calm and keep inhaling slowly, to let the vapour deep into your lungs. By doing it slowly and relaxed, you can suppress any coughing reflexes. You need to get the DMT vapour in deep into your lungs and hold it in for a while to let it absorb into th bloodstream.
While doing the inhaling, try to keep the bulb heated and the DMT bubbling, pulling in more vapour with the passing air you are sucking through the pipe gently. When you're pulling air through the pipe, there won't be white clouds visible like before, but you're still getting plenty of DMT out.
Keep inhaling deeply until your lungs are full, then put away the pipe and the lighter and finally put yourself away on a place that is comfortable. Preferably you have prepared the place and tested it for comfortability (tip #3a: make the comfort testing part of the pre-flight meditation.)
Keep the DMT vapous in as long as comfortable to you and after you slowly exhale, slowly inhale a deep breath of fresh air, to supply yourself in the trip with plenty of oxygen. By now, you should be disappearing into hyperspace.