It is a bit difficult to write about the opposite gender. What makes it difficult is that you have to know how the minds of these people work. Eachperson's mind is unique, so you need to develop your character. If you have been watching a lot of movies, you could simply stick to the stereotypical behavior of the opposite gender. If and only if you are really having difficulty, you could set the personality of your protagonist to a bit "tomboyish".
If all of the above fails, I would simply ask a person of the opposite gender questions that are relevant to the story. You may ask them about reactions or such. You can also observe their behavior (not in a stalker kind of way) and see how they react to certain stimuli. You do have to choose your subject wisely though, and ask permission first.
When writing about the opposite gender, take some time to consider what they would do, say, or feel.
P.S. Usually, within the dialogue of females, their use of language is reasonably refined, thus swearing is limited.