I'm not sure how many people here have used Pen Tool (the icon with a little pen) in Photoshop before, but personally I think it is quite a useful tool when it comes to outlining and creating custom shapes.
In the beginning the Pen Tool can be a bit awkward to use, but once you practice and get used to it it will become a very handy tool for you, especially when you are trying to outline objects with complex lighting and backgrounds.
I'm also learning the Pen Tool at the moment so here are some tutorials I found on the web covering the use of Pen Tool in Photoshop:
Firstly some basic knowledge about Paths and Pen Tool, from beginner level to advance level:
Paths and the Pen tool
Secondly have a go with this outlining object tutorial:
How to Use the Pen Tool in Photoshop: A Tutorial on Outlining Objects
For deeper readings, take a look at this article:
Pen Tool Tutorial - Creating Selections With Photoshop's Pen Tool
Hope those info helps
