From my understanding, there is more than one element you my choose to associate yourself with and work with. Keep that in mind as you try to find "your" element.
Some basic ways I would suggest involve meditation and exposure to the various elements. Spending time working with each one is a great thing. Most would say that "your" element(s) will be the one(s) you feel strongly connected to, and the ones that appeal to you the most. Follow your instinct.
Some others use their zodiac signs as a starting point. You may choose to do this as well. Another great way would be to focus on specific elements before falling asleep, then write down your dreams in a dream journal the next day. Was there an element in your dream? What happened with the element? How did you feel? Etc.
There's probably a ton of information out there that I didn't give, as this was very basic. I suggest looking in the articles, using the search bar, etc.
Here are other articles/forum posts you may wish to invest in. Be sure to remove any spaces that appear in the link: