Dressing up for work

[oursouls]

I have to wear an issued t-shirt for work. It is your basic, gildan, cotton t-shirt. I can wear whatever else I want with it, though covering the staff part on a daily is a no. I am a senior staff member and a director of a program so I'd like to look some what like a dressed adult and less like a thrown together kid. I tried wearing cardigans with it, but again, covering up the shirt is not okay on a daily basis. I bought some fun earrings and have been putting more effort into my hair and face, but I'm really missing the mark for clothing.

Any help? How would you make a basic t-shirt look a little more adult?