Nondescriptive verb:

I was an accounting assistant in my most recent internship.

Descriptive verbs:

I provided accounting assistance in my most recent internship.

I served as an accounting assistant in my most recent internship.

Nondescriptive verb:

I did consumer surveys during my summer employment with a marketing research firm.

Descriptive verb:

I conducted consumer surveys during my summer employment with a marketing research firm.

Nondescriptive verb:

I worked in magazine advertising sales over Christmas break.

Descriptive verb:

I sold magazine advertising over Christmas break.