There is no real "LIST" of sins, SIN is any "wrongdoing". Repenting means STOPPING the INTENTIONAL "wrongdoing" and not repeating it (by being careless, you might eventually repeat the wrongdoing, but as long as you are making the HONEST effort not to repeat the wrongdoing, you are REPENTING).
That's the most straightforward explanation necessary. Of course we are to be REASONABLE about this and not pick on ourselves so that we feel guilty about little things like getting mad at someone.
I have been a Christian for 17 years and realize that you will hear many prudish explanations of what a SIN is, but it is a matter of the heart what you consider that God doesn't want you to do and what is Godly behavior (Ephesians 5:9 "(for the fruit of light is everything that is good and right and true)")