Also look here for a few more general errors/reminders..
Remember your purpose: you're trying to come up with 1 idea, supported by three examples;
Don't create a "speculative" argument in which you advocate 3 different views, essentially "three reasons I think my opinion is true."
Also, make sure your thesis is specific enough to be saying something. (don't argue for instance, that "lying can be bad" or "people should make good decisions, " etc., as these are too broad and too obvious to be saying anything at all)
Use the 2/3 rule to make your argument's thesis meaningful:
OUTLINE before you write: make sure all your examples show what you say.
EXPLAIN each of your 3 examples: HOW exactly does each example show your point?