The right placement.
Sharp and even curves.
Tips that come to a clean point..Well I can't tell you how to put the black in solid (you should already know how to do that) and I cant tell you where to place the tribal (the placement works best with the curvature of the muscles) but what I may be able to help you out with is smooth curves and tight tips...when I do any tribal work (and I do a lot of that in our shop) I use an eight needle outliner...I guess by now you must be asking why an eight? I thought that you said the tips are going to be pointy...well I use an eight needle outliner because it produces a wide enough outline that you don't have to slave over getting up to the outline without going outside the outline with the color, and this makes the job goes much faster.
Also with a wide outline it is much easier to produce a nice curve or straight line then it is using a five needle or a three needle...but now you ask yourself, but what about those pointy tips of the tribal that you talked about? See when you turn the flats sideways you produce what is equivalent to using a single needle.
Because all the needle on a flat shader will produce a line that is as wide as a single when used sideways...like I said in my other tech tips.
This may not be for you, but it sure works well for me and also for all the other Tattooist that I turned on to this