The pronoun I has no place in a resume -- and for a logical reason: Who else would you be talking about if not yourself?

Instead of this:

I demonstrated professionalism, tact, and diplomacy while I worked with our customers in high-pressure situations.

Write this:

Demonstrated professionalism, tact, and diplomacy while working with customers in high-pressure situations.

Instead of this:

I managed a department whose chief responsibility was to oversee safety audits. I wrote all audit reports and conducted management briefings.

Write this:

Managed a department whose chief responsibility was to oversee safety audits. Wrote audit reports and conducted management briefings.

Notice that the second version of each example begins with an action verb. Beginning most of your sentences with action verbs may not have been standard practice when you were writing term papers, but this practice is accepted and recommended in resumes.