I throw needles and can stick them to about 8-10 feet. I use a style based on shuriken throwing but it is my own variation. I throw doll making needles which tend to be longer than most needles, from 4-7 inches.
I also throw shuriken. My favorites are made by Jeff Adams and are identical to this set:
http://www.secrets-of-shuriken.com.au/images/jda01.jpg
I hit at about 90% at 8-15 feet and am at about 60-80% at 15-25 feet or so.
I could not find a technique for throwing needles, I did read that one man who mastered it said that he practiced until he could do it, but he could never teach the skill and his students never picked it up. I'd suggest that you do the same thing, practice.
I use a direct hit method for shuriken and needles, though a half turn works well too at longer distances despite not being required for either. I practiced throwing needles indoors and into cardboard, starting close and making thousands of throws before I got any great results.
Let every failed throw motivate you to be calm, patient and try again.
With needles and shuriken I don't throw them, rather I let them throw themselves so to speak, I merely guide them. I use my elbow as a fulcrum and line the projectiles up with my forearm. I fling and push at the same time and let the motion make the needles or shuriken fly out from my hand on their own, instead of trying to throw them or put force into them. It works best when you are relaxed and gentle yet firm, increase the speed for increased power once you get good results, but start out gentle and relaxed.
My arm is never sore from hours of "throwing" these light projectiles. I find their use to be a form of meditation but often put in over an hour a day of practice. I also practice two approaches, I do use conventional or traditional methods to throw, but I also use my own methods, I am much better with my own methods than with convention.
Try to keep in mind being gentle and that you aren't throwing so much as guiding them as they fly out from momentum. This will allow you to throw them quickly while largely relaxed and that will give you greater control over them.
Here is a poem about the act of throwing them:
I am not throwing,
Your path only starts with me
And away you go
I do not throw you
I merely start you upon your path
If I guide you well
You will reach your destination
You leave of your own will
Sliding through my fingers
Through the air,
To stop and tell of your arrival
Emissary of myself
Go quickly and calmly
Forward pressing firmly
with sharp and gentle touch
