You should try to avoid making vague or wishy-washy statements. It's a pretty obvious sign of confidence. Of course please don't go overboard and try to talk like a robot.

In English language terms, "sometime" is indefinite. Substitute it in your sentence for "maybe" and see if you think there's really any difference.

Otherwise a lot of these things are filler and make you sound like you don't know what you're talking about. Picture a good public speaker like Obama or the late Steve Jobs making a speech full of ums and uhhs and see how that would affect your perception of them. Much better to pause and be silent than use some filler.

Of course please don't go overboard and try to talk like a robot.

The word "like" is the worst word i have in my vocabulary.
I'm starting to do exercises from "The Rules of the Game" so I can erase all my ums, uhs, and likes from my vocabulary.
One of the best things you can do is record a conversation with one of your friends and review it later on. Write it out word-for-word as you hear it, and see how many times you have that crap come out of your mouth. I have the worst habit in the world of calling a woman "Dude". Not for long, hopefully!