This is a good start for a first essay. Looking ahead, you will need to work on grammar and word choice, in order to ensure that your arguments are understandable.
A trivial change can have a big influence. Obama is such an example. It is a little change that let him succeed.
I'm not clear what you are saying here. What "small change" allowed Obama to succeed?
That he invested a lot of time in community service let him got a lot of countenances in precedent election.
I'm sure that you mean "presidential" election, but I cannot guess what you mean by your use of the word "countenance." I'm guessing that you saw the word in a translator or thesaurus. Before using a new word, be sure to read all of its definitions and associations in a dictionary. If in doubt, use a simpler word that you know well.