There are plenty of techniques for doing masking, some uses channels, color range, pen tool and lot of times for those who has a tablet they just paint it with their brush tool.

For me I use free hand masking for those edges who needs additional details, I have here a perfect example of a photo which I bet you won't use your favorite pen tool or your free hand to pick the capsule.

You can find the high resolution of this source in here, a forum on photoshoptalent.com. (sorry for the broken link, may 2009 when the photoshoptalent.com server hosting been corrupted and all files are gone.) but they lauched the same contest in here

Our goal is to pick the capsule out there so we can use it freely. And you can see how detailed the capsule was, you won't be using your pen tool for sure.

I am going to show you how to pick those by evaluating the color first, Definitely we saw two main color red and raw sienna. But if you try to pick it using color range, there are still plenty of noises inside and out.

So our goal is to make the color of the capsule stronger by adding adjustment layer, and on the blue adjustment channel bring the graph down to its lowest point.

Now that we take down the blue, it's simply means that our photo now doesn't have any blue at the moment; we will take advantage of that by taking down the red by adding Hue/Saturation adjustment layer, and make sure to choose red and take it down to -100.

Now take a look at that, that makes the job easy isn't. But it's not done yet.

Next step is to select it using color range. Make sure to add detailed color so I suggest you zoom in before using color range.

Then select the original layer with the image and hit mask button. Then [Alt Click] your mask and clean it up using brush tool. just clean up the background not the inside.

I'm pretty sure you're not happy with that mask, We are going to make it more stronger. [Ctrl Click] the mask to select the white area then press [D] to reset your fore/background. Then press [Alt Del] many times as much as you want.

Delete the curves adjustment and the saturation adjustment layer, and then you're done!!

To test it, apply some manipulation on to our capsule, I cloned the wall and use the liquefy to transform the capsule in that shape, and this is how I end up.

Pretty Cool isn't it? try it and give your best shot ^^.