College essays are about selling yourself. The best way to sound confident without outright telling the reader so in your essay is to write a story that shows you are confident. College essays are the only time you get to talk about all of the wonderful things that make you you without anyone judging you for it.
You'll have to think carefully and decide which strategy is best for you. This is, after all, your last chance to persuade your readers to your point of view, to impress yourself upon them as a writer and thinker.
Some students find ending their essays a snap, others get a bit lost at the end and veer off track. Don't undercut your authority by saying things like, "this is just one approach to the subject; there may be other, better approaches.
Bring the reader up to date to the present. If you thought becoming a ventriloquist as a kid was really cool and eventually gave it a shot, write about it.