Discuss skills that you have improved upon during your previous job, so you are showing the interviewer that you can make improvements when necessary. You can sketch for employers your initial level of functioning, discuss the steps you have taken to improve this area, and then reference your current, improved level of skill.

If you use this strategy be sure not to mention anything that you improved upon that is related to the job for which you are interviewing. You don't want your qualifications for the job to be questioned.