Here is a site to see:
Use VERY SHARP hair cutting scissors or paper cuttng scissors (but it must not be dull!)
Cut only between 4-7 flight feathers on EACH WING.
Cut 4 one each wing at first and then wait 5 days for him to settle in and for your to determine how much more should be clipped. With larger species of birds only 2 flights should be clipped on each wing and then waiting several days to determine if more need to be clipped. Do NOT clip ALL the feathers you want to be cut, this is NOT how it should be done and is very stressful and traumatizing to a bird.
The point of clipping is NOT to get the bird to not to fly, but to have a controlled flight. A bird who cannot fly or glide or move around with his wings, is an unhealthy bird. He should still be able to flap around a bit, but it should be controlled. Flight is the #1 best exercise for a bird. Playing with toys and moving around doesn't come close to flying.
After several days with 4 flight feathers clipped on each wing, and you think more should be clipped, clip 1 more on each wing. See how he does, is he still beaming around the room like a torpedo? If so, clip 1 more on each wing, and one more if needed. I personally wouldnt do more than 5 for a small bird such as a plet. For bigger birds I think no more feathers than 4 on each wing should ever be clipped. As again the point of clipping isnt about getting a bird land bound, but controlling their flight, so when they attempt it, they dont go far, and its not out of control, chasing the bird aorund the room, type of thing.
Here is a site that should how clipping should be done, it has pics:
Parrots - Clipping Parrots Wings - Learn how to clip parrots wings
This site has steps on how to clip:
How to Clip a Parrot's Wings | eHow.com
If you need more info, go to google.com and type in :clipping a parrot's wings" Or "How to..."
Thoughts on wing clipping:
Thoughts on Wing Clipping