What is the best way to get elected? are there certain things i should do or uprades i nedd, every tim i try i lose. I've really only tried with a theif profession though, does that matter?

You can find out who is going to vote for your office of choice by going in the City Hall and looking around there (not sure what you click on to find out but I know you can). Once you find out who is going to be holding the meeting for voting, you can then proceed to brib/improve your standing amongst the voters and get into office that way.

Yes, your profession has an impact on your standing with the officials (which is described in the manual, in the part about the new features in the expansion, on page 11), which, in turn, has an effect on your chances. The thief has a penalty ranging from -3 to -12 percent among the various layers of society.
But, as Judas pointed out, there are always ways to make them like you more. Or, you can make an appointer and a nominee like each other less (Bloom of Discord /from the Perfumer or Herbs and Phials/, Tirade of Hatred /Church, Brian's Bookshelf/). IIRC, you can find everyone involved in the voting process among the "important people" section of the "Office overview".