I think the main thing is too inhale as much of your dose as quickly as possible then hold for ~15 seconds. If you inhale the full dose in one inhalation then hold until you disappear.
If your smoking device and technique are well enough (imo GVG or bong, carefully apply heat) you can achieve breakthrough on your first hit.
My rule of thumb when I was starting was when I felt like I had enough I would take one more hit. Enough for me was when I could barely understand how to work the smoking device and my fellow travelers faces were transforming into elves, I would take one more. For the 3-hit method I find the first hit is almost like instant meditation, a very calm headspace and mild visuals. Second hit I feel the energy begin to rise through my head and visuals increase. 3rd hit would hopefully be a breakthrough or else subbreakthrough (still aware of body but strong OEV/CEV).
The problem with the 3-hit method in my experience is that it can be more difficult to achieve breakthrough. Most likely due to the increased time of administration (Hit 1, hold 15s. Hit 2, another 15s. By hit 3 you are almost at a minute).
Most devices can hold enough DMT for a breakthrough so I woukd suggest practicing your lighting technique to better vaporize the product. Do not touch the flame directly to the DMT, let your inhalation pull the heat from the flame towards the DMT and slowly it will vaporize. You can also try making an Enhanced Leaf or Changs blend as both should be easier to avoid burning and get a proper dose.
The inner soul is full of joy. Reveal my secrets and sew me whole. With each day, "I" heeds your call.
You may not care the slightest and may not be the brightest, but from here "I" sees you're mighty for you created it all.
And the jumbling sea rose above the wall.
Through this chaos comes the order you enthrall.