There are multiple ways to select items in Photoshop. Choosing the appropriate one depends on the object being selected. Try the following selection tools on the images identified. Below is a list of the different selection tools and what they are best used for. Try the sample image for each one to get the feel for how each one is used. Always remember to close a path (look for an "o" symbol that appears when linking up a starting and ending point) when using a selection tool that involves drawing outlines.
Quick Selection Tool (command + W)
This tool "paints" a selection by automatically finding and following defined edges in the image. This is the most versatile and easy to use selection tool.
Magic Wand Tool (command + W)
Groups and selects pixels of similar colours together to make an intuitive selection. Good for odd shaped areas that had a specific colour range.
Polygonal Lasso tool (command + L)
Used for selecting shapes involving straight edges. Click and create lines between anchor points in order to fully outline and select a relatively geometric object.
Lasso Tool (command + L)
Used for tracing a freehand selection around an area.
Rectangular Marquee Tool (command + M)
This tool will select and cut out a square (or oval) of your own creation. This is ideally used for cropping or selecting a square or circular object in an image.
Magnetic Lasso Tool (command + L)
Use this tool in order to trace complex objects with a clear and defined edge. It automatically snaps to a perceived contour and creates anchor points while you are doing a freehand selection.