One of the reasons why Jefferson's document possesses so much beauty is that it takes a subjective experience and makes it universal. For example, the problem of which he is writing concerns the colonists and the British. This personalized notion of narrative is "universalized" through the opening lines: "When in the course of human events..." The implication is that the struggle for acknowledgement and recognition is not one only limited to the Colonists, but rather one to which anyone can forge connection. This universal appeal is not only one of the reasons why Jefferson's document is so revered, but might also underscore why the American Revolution was so powerful in its implications. In terms of writing your own introduction, I would try to follow the same guidelines. There is a way to make the individual struggle for freedom and recognition one that can be connected to by anyone if the language and tone strikes this idea of forging bonds. I would start by analyzing how others can appreciate and understand your own predicament. Writing with this in mind, an aspect of audience, could help to make a very strong introduction.
I agree with the previous poster. I would add that it may be helpful for you to review the structure and argument of the Declaration of Independence. Consider how you might echo some of the original document even as you adapt the text to serve your own ends.
"When in the Course of human events it becomes necessary for one people [you could change this to "one person" or "a young man/woman"] to dissolve the political bands which have connected them with another [you could change this to "his/her parents"] and to assume among the powers of the earth, the separate and equal station to which the Laws of Nature and of Nature's God entitle them, a decent respect to the opinions of mankind [you could change this to "common sense"] requires that they should declare the causes which impel them [you could change this to "drive me" or "leave me"] to the separation."
Make as many changes as you can in order to really make the new text fit your particular writing situation. Also, if you want, you could go on to list your grievances and your resolutions.
This strategy really isn't plagiarism; it'd be more accurately called adaptaton or appropriation. You wouldn't be the first to do it, either. See the second and thrid links below for examples of adaptations from the Vietnam war era. If you doubt that the readers of your document will recognize your piece as an adaptation or appropriation, though, you may very well want to err on the side of caution and add a note at the bottom of your document that reads something like: "Inspired by and adapted from 'The Unanimous Declaration of the Thirteen United States of America.'"
It depends... are you talking about a declaration of your own personal independence (like from parents) or are you supposed to be doing one for a country?
At any rate, I guess it comes out the same... the one that Thomas Jefferson wrote starts out, as you know, by laying out the philosophy for why the United States SHOULD be free. He talks about the ideas of life, liberty and pursuit of happiness as the things that government has to protect. And he argues that if the government doesn't then the people of the country should rebel against that government.
So if I had to do your assignment, I'd try to figure out something along those lines -- why it is (in theory) that you or your country ought to be independent.