Was pretty bored, so I put together a little tutorial on paths in case anyone
was interested ...
First thing to do is select the path tool (circled in the first shot), then create a rough outline by selecting several points (nodes) around the area you want to select. Don't worry too much about detail at this point, you can make alterations as needed.
Once you have your basic outline, select a node you'd like to adjust by clicking on it. Be sure you are also in "edit" mode by double-clicking the path selection tool to bring up the tool options dialog. Each node has a pair of handles you can use to manipulate the paths connected to it (as seen in the third shot). Drag the handles around a bit to get the hang of it.
Note that the handles are initially at the center of the node, so you will have to drag them out from the node to access them.
When the mouse cursor is above a path (the lines which connect nodes), it should become a "+" symbol. Click once with the left mouse button to add a new node at the current location. Don't worry if it's not exactly where you want it, you can move the node around afterward. You can also delete a node by holding down shift while clicking on it.
To move a node, first select "design" on the tool options dialog from before. Then simply drag the node to the desired location, the path will adjust automatically. Finally, once you're happy with the path you've created, click on "create selection from path" in the tool options dialog (circled in the sixth shot) to get your selection.
TIP: If the path is somewhat difficult to see on your image, create a new white layer and make it slightly transparent. That way you can see the image underneath, but also have enough contrast to see the path you are working on.