If you are giving a student council speech and want the other students to vote you in as secretary, you need to focus on two things:
What you are saying, and the way you say it. The latter is perhaps even more important that the former.
I once watched a British TV documentary about people who wanted to be stand-up comedians. The show was presented by a well-known and popular British comedian, who gave advise to other comics. One man couldn't understand why he wasn't getting anywhere - he worked hard on his jokes and read all he could about the great comedians of the past.
However, as the professional comedian pointed out, this guy hadn't considered how he appeared on stage, where he was nervous, shifty and reluctant to engage with the audience. To get people on your side, he explained you need to appear confident, positive and forthcoming, even if you don't feel confident. I think the same is true of making a speech.
If in Doubt, Steal!
If you are giving a speech, project to the audience. If you don't feel confident, then fake it. Study film of people you admire giving speeches, even if it is an actor performing a speech in a movie, note how they engage with the audience and yourself.
Ask yourself why you admire this person and copy the style of their speech. After all, no-one needs to know how you are giving your speech, they will be interested in the speech itself, if you are delivering it well. If you like President Obama, watch how he gives a speech and remember he too will have had professional training on how to deliver a speech.
As for content, that depends more on personal circumstances. It couldn't hurt to ask around to see what people would want a student secretary to do once in office. Ask students directly or listen in on general conversations, even outside your usual circle of friends, to get some idea of the hot topics around college.
And this YouTube film will show you what NOT to do...