Are you sure your layer is transparent and has no background on it? If you are working on a flat image that has a solid background, adding a stroke on the layer will add it around the whole canvas, not the specific part you want it to. If that's not the case, make sure that you have Center or Outside selected for the stroke in case there's a layer on top of the one you're selecting that's covering the stroke.
well, there are two ways to create a stroke and are you sure your using a color other than the background color? Also, I usually stroke center, if it's interior or outer and of the same color as either, respectivly, you won't see it. And of course, is the layer your selecting on a transparent background?
yeah im using a color other than the background i actually switch between different colors but nothing happens also i am not doing it on a transparent layer because i already made a copy of the original background and started working on it . but you said you stroke center i thought u were supposed to stroke outer to render that highlight effect around an image? im confused
Ahh, well, yeah. You could make a selection, stroke that and then gausian blur or just use the "outer glow" effect under layer effects, you can right click on the layer effect and make it a layer unto itself and then play with it independently. For the stroke to work you either have to have a selection or the object has to be on its own layer. You can also stroke a path by useing the pen tool to creat the "path" and then right clicking and selecting stroke. If your object is on a layer with a background then all your going to stroke is the edges of that background, in most cases that would be the edges of your canvas.