Greetings and Salutations to the Newly Admitted!
I don't have a link right now for any good plastic effect tutorials and I'm sitting in my college cafe so I can't open PS and tell you step by step what to do. So I'll have to use my super memory recall powers to summon them out of the abyss that is my mind!!
Note: All this is useful if you have some knowledge of Photohsop
First off; I have no idea who Lance Armstrong is so I can't relate to the said braclets. But if you want to make a plastic effect then you have to know a few things.
First, the effect our eyes see of plastic is a play of shadows heck everything we see is a shadow matinee!
You've got to incorporate these shadows in such a way using Photoshop that they seem to be plastic like. How, this is seeing you're subject is light in color, is by adding a faint (not too faint) Inner Shadow. If you want it to be glossy then all gloss is is a very bright spot on your subject. Just use Bevel and Emboss and the curved contour to get that effect plus play around with Soften to make it nice and smooth just like plastic was meant to be!
Now you have a plastic object but it's partially invisible because it has no depth. Depth is how you see everything around you. The farther away somthing is from your eyes the more the depth. To mimic that in Photoshop we have Stroke and Drop Shadow. Since it's plastic and by what I read you are looking for a photo realisim then stroke shouldn't be too much thick just 1 or 2 px depending on the size of the subject, and it should be faint in color. If the subject is light then the stroke should be darker, preferably black, to show the depth.
Now to top it all off a fuzzy Drop Shadow indicating it's density. Since it's plastic it's going to be semi-transparent then the shadow must be pretty darn fuzzy so increase size and lower opacity to show the transparency. If the subject is not transparent then lower the size and increase the opacity.
Finally make sure the lighting is according to the light source of the gloss if there is any. That will ensure the photo realisim of the image. Do this is you intend to make the image photo realistic.
If you take note of these few concepts i.e. Lighting, Depth, Density, Gloss etc making photo realistic images will be much much easier. And of course if all this mumbo jumbo just pass over... your luck!!
No seriously if you still don't understand I could type in a short tutorial on how to do it once I get to my own PC.
Cheers!