Stiletto nails are almost always made by form-sculpting with acrylics. The form is rolled tight and narrow at the tip to create the very pointed tip (designed to look like a stiletto heel)..
Check out a some selected stiletto nails below:

First saw them here on Rihanna, I wasn't convinced....
...until she did them nude! I now fell in love with them!
How lush do they look?
You can get real edgy and do them white...
Amber Rose makes the white look really cool!
These are MAJOR!
I'm not that wild when it gets to nails, this pink is the wildest i'd go.
I'm not one for patterns either, but I'm feeling this!
This design is cute and fun!
Yah! Who doesn't love bling?! We all do!
hahaha! 'F**k love' how creative...
Oh yes! The owner of these nails deserve a round of applause! There yummy!