Use terms and phrases that are meaningful to the employer.(This is where your industry research and networking come in.) If you are applying for an advertised position, use the requirements in the ad and put them in bold type. For example: the ad says
"2 years' experience processing magnetic media (cartridge, tape, disc); interface with benefit plan design, contracts and claims; and business background with strong analytical & technical skills--dBase, Excel, R&R, SQL."
Make sure your cover letter contains each of these requirements and shows how you measure up.