Activate the "testingcheats" code and enter the following codes (without the quotes) at the console window to enable the corresponding career.

Promote Sim in Current Career:
Enter 'Careers.promote (career name)'

Demote Sim in Current Career:
Enter 'Careers.demote (career name)'

Adds a Career:
Enter 'Careers.add_career (career name)'

Remove a Career:
Enter 'Careers.remove_career (career name)'

Raise Child's Grade by One Letter:
Enter 'Careers.promote Gradeschool'.

Raises a Teen's Grade by One Letter:
Enter 'Careers.promote Highschool'.