Lasso Tool

• To select an area In the Toolbox, select the Lasso Tool, click on the image and draw a contour holding mouse's button pressed*(or simply draw if you use sylus).
• To close the contour just release button if you draw with mouse or uplift stylus.
• While New selection option choosen on the Options bar by creating new selection you delete existing one.
• To add an area to existing selection you have either to choose Add to selection option on the Options bar or to press (and hold) [Shift] key while selecting.
• To subtract an area from existing selection you have either to choose Subtract from selection option on the Options bar or to press [Alt] key while selecting.

• To intersect new selection with existing one either choose Intersect with selection option on the Options bar or press [Shift+Alt] keys while selecting.
• While New selection option is chosen and the point of cursor is within selected area the tool looks like this and can move selection (ie. borders of selected area and not image content).
• While New selection option is chosen you can also move selection using keyboard cursor keys.

Tip. Just in case you didn't know, the Lasso tool is also available in Photoshop Elements that is way cheaper version.

And if you believe, Photoshop Elements lacks some other important feature, be sure to visit this page.