If you want to make it super explicit, come up with examples. "Be bolder, for example for this project I saw you doing 80% of the work, you should get to headline the presentation and have top billing on the authors page".
"Act like X" is also potentially useful, if you make it explicit. Explicit is not "Act like a white man" (whaaaa?). Explicit: is "Act like Bob, for example do you remember when HR said he couldn't have a new screen and he insisted"?
It's just an extension of the classic "show, don't tell".