How to Get a Smaller African American Nose Tip?

There is generally no single maneuver to create the well defined tip in a "typical" African American nose. As you have stated and have been told in the past, it is more difficult to obtain extreme definition in thicker skinned noses. That does not necessarily mean that you cannot have significantly improved definition when the surgery is performed appropriately.
I have a large ethnic population of rhinoplasty patients and the metaphor I use to explain the changes we are going to make to the nose is as follows: Your nose shape and size has a great deal to do with the framework that the skin lies over. Like a tent, if the support structure is placed in a trapezoid shape, you will have a trapezoid tent. The skin (or canvas of the tent) simply drapes over the structural support that we create with cartilage, bone, and occasionally implants. If your tent (nose) has a very thin canvas (skin) then every detail of the structure beneath that canvas will show through the canvas.
If you have a very thick canvas (or thick skin), the surgeon needs to accentuate the structure of your nose so that it will show through the skin, giving you more tip definition. How this is performed will vary but, you can expect a combination of tip sutures, tip grafts, and what we call columella struts. All of these techniques lend support to your tip so that your tip structure will support the skin envelope and thus, give you more tip definition.
Finally, your surgeon may also elect to thin the canvas (skin) by defatting the skin, but this will be performed in a very conservative manner. Hope this helps.

Typically a compbination of procedures are performed. Commonly, a reduction of cartilages and stitches to control the shape with conservative defatting of the skin with selective grafting of the tip and dorsum to provide enhanced definition and projection is performed in combination with nostril wedge resections.