Well, it surely depends on your faction but in general it would be a good idea to contact your faction leader/ join your faction's forum and ask for a job.
As Yasira Shran already stated, if a faction already accepted you, it's up to them to provide you with a job (best would be to contact someone within the faction. Most likely it'd be the person who recruited you, the person who accepted you into the faction, or someone similar.
Personally I would suggest messaging the leader of your group (if it is a smaller group) and asking him what sort of task he/she wants completed. Perhaps there is a message board for your group that you can register for and post on?