When I'm not given a suggestion, I try to make an arbitrary declarative statement to myselft about my character.
For Instance:
"I never want to get married."
or
"I think all children are spoiled."
or
"I'm greedy." .. etc.
Now, in your opinions, is it better to hang on to that and inform my choices with that statement, acting as the kind of person I think would make a statement like that OR should I come right out and say it, pretty much verbatim, at the top of the scene to clue my scene partner in to the kind of character their character will be dealing with?