Answer:
If either part of the compound subject can be used (correctly) as a subject by itself, then it will work in a compound subject as well.
Explanation:
Me and Frank thought it would be a good idea to review before the test.
Frank works, but does Me?
Me thought it would be a good idea to review before the test.
No, it should be
I thought it would be a good idea to review before the test.
And then we never put ourselves first in a compound subject, so the correct compound subject would be
Frank and I thought it would be a good idea to review before the test.
