Just ask for a small percentage more than offered and plan on changing jobs after a couple years for your first real raise (20%+). Most places will try the 'you've been super awesome so you get the full 3%' trick, which is basically just the inflation rate. Don't expect miracles. Don't try to use an offer to try and get a better one somewhere else. It's kind of unprofessional. just say 'I really need $x to accept your offer'.