OK, I promised to tell how I use Pen Tool for isolation of objects. Indeed, there are some small tricks which I use in every type of isolation, and I'd like to share them with you.
First thing you should remember about Pen Tool is: don't make too many points trying to repeat the contour of the object. It's better to curve the lines in order to get smooth selection without sharp angles.
Let's take this example.
The color of the background is very close to the color of the hammer, so it'll be difficult to use Magic Wand Tool in this case. In order to make a selection with Pen Tool, we should click to create a starting point in the bottom, then one more point above it. Now we have a straight line, Let's make one more point in the center of this line, press Ctrl and drag this point to the left.
You'll see that our line becomes a curve. To make the curve of the form we need, press Alt and drag the "whiskers" of the point:
When you finish making your path, click the right button and choose Make Selection. Now go to Select - Conract and contract your selection on 1-2 px. Then Select - Smooth and smooth your selection on 3-5 px. Then Select - Feather and feather your selection on 1-2 px. Now you can delete the background. You'll see that your selection is precise and a bit feathered.
Don't forget to create your path 1-2 px away from the edge of the object in order not to take the background into your selection.