Maschinen is correct, however to answer your question re: lowering faction points, one way is to take Imperial delivery missions. *WARNING -the following advice may lead to boredom and/or lessened brainwave activity!*
Take the lowest paying missions possible in a town such as bestine and just run info back and forth. Lower reward = less distance running. Two missions at a time give you 12 points each run and you get no negative Reb faction. Plus you make just enough to gas up your Dad's Landspeeder after that big date in Mos Eisley.