1) Set aside just half a cup or so of the cheesecake batter.
2) Stir into it about a teaspoon of SIFTED (so it won't be lumpy) cocoa.
3) Drizzle this cocoa-colored batter in parallel lines over the batter you've already poured into the pan.
4) Then moving in a direction perpendicular to the lines, use a toothpick or chopstick to go lightly through the lines: up once and then down once, and then repeat.
5) Voila! You'll have a gorgeous, extremely easy-to-do feathered look in just a minute or so, and the cocoa you've use is so minimal that it won't add any taste to the cheesecake as a whole.
A super easy solution - add fruit to the top. Berries work really well. You can put them in a pretty pattern or just sort of pile them on top. Another option is to drizzle chocolate or fruit sauce on the top - this works well in addition to the berries too.