Also, do not overtighten. If there is any looseness, then once the tank is fairly well cinched up, watch as you slowly turn to see if the wick is being sucked into the chamber. Redo and correct and then backoff just BEFORE, the chimney starts to suck up the wicks. Sometimes, too much wick will press against the tank, and the tank will turn the chimney chamber and suck up the wick. After a few tries, you'll be able to see the turning, and will learn to avoid. Yes, new O-rings always helps. As inexpensive as good O-rings are, many vendors still use poor performing O-rings, particularly in the clones, but I've seen them less than perfect in the authentic Tai's as well. Once you know what's going on, by watching the wick and chamber, and turning the other parts, you'll see what's going on and intuitively understand how to reduce the tendency, if not completely eliminate it.
The other thing that can happen, is the chimney/chamber will be too low and the tube on top of the chimney, attached to the cap, won't seat correctly. you can tell if the tube o-ring is visible. It should not be visible, but if it is, you will get leaking. Leaking happens when the tube doesn't seat correctly, the wicks don't stay seated, or the wick material is not dense enough to prevent flooding at the chimney wall. When any of these happen, Leak City. Sucks. Like all devices, there's a wee bit of a learning curve and the Tai is no different. that being said, once you get used to the Tai's peccadilloes, a tensioned micro coil wick proper wick density, seated correctly, will all contribute to one of the very best RTA vapes you can achieve. Once I got the Taifun, I pretty much retired the Kayfun's, and a dozen other RTA/RBA's. My four Tai's are now in rotation for the missus and I. Lovin' the vape these days. I like TMC's around 1.1 - 1.5 ohms with 29 gauge on a 1/16" mandrel. Also, I DIY, so I can flavor my juices to operate under these conditions. Nirvana. My experimentation has almost become non-existent these days. Some friends are sending me some KGD, so maybe the vape will improve again. We shall see. Pretty darn good now! Good luck to you. Sorry for being overly technical. Keep asking questions until you understand the fine points, and you too will have a great vape! Best.