Good advice here. When Castor was a pup we hid treats in empty cardboard boxes and rolls, which he thought was great fun. We started out with a piece oif kibble in an empty paper roll that we folded so that the kibble wouldn't escape. When he had got used to those, we hid them behind doors, for instance, and encouraged him to seek for them. Now, he's soon seven, and not very interested in such play, but as a pup he loved it!
I'm not sure how important this is (and I know different people have different ways of playing/interacting with their dogs), but I actually would be a bit hesitant to engage in tug-of-war play. You might not want a full-sized bulldog to hang on to things, so unless you train her to let go on your command, I would avoid tug-of-war activities. Even a gentle soul like Castor has enormous power in his jaws. He is a bit stubborn (or perhaps not well trained enough!) and actually doesn't let go at all times, but I can always put my hand in his mouth and pull out a stick or ball. If he had been allowed or encouraged to hang on to things, I'm not sure I would have liked to stick my fingers into that massive mouth.
