It is one of the basic, fundamental beliefs of Wicca (and the occult in general) that the Elemental forces of Earth, Air, Fire, Water, (and the "Fifth Element" of Spirit or Ether, which includes and contains them all), are the basic forces of existence and action, that which forms the very foundation of all manifestation- in simpler words, everything started with the four elements.
To work effectively with the Elements, it must be understood that with all forms of energy or force, the Elements themselves are polaric in nature, having both creative, and destructive aspects, each of which must be recognized and balanced with its counterpart in order to achieve a productive harmony.
To understand each of the Elements, you must also have some level of understanding of each of the corresponding elemental planes, the hierarchy of its inhabitants, the forces that govern these Realms (this is more advanced Wicca- for example, the forces that govern water are called the Undines), and how they affect and influence us in the everyday world.
There are countless methods to be used for getting 'in touch' with a particular element, such as projecting the thought of an empty shell of yourself being filled with the appropriate elemental color, scent, sound, until you achieve the desired effect, or you can try projecting your consciousness to one of the elemental planes. Please do not try this without further information, for Wicca this advanced could be harmful to a novice. The best advice I can give is to do what feels comfortable and right to you, whichever method you choose on, always use common sense, and respect that which you learn.
THE ELEMENTS:
Air
Fire
Water
Earth