“Decide what kind of member of Congress you want to be,” says Tom Davis, the former congressman from Virginia. “Voters see through phoniness pretty quickly.”

Davis, who chaired the Republican campaign committee and House Oversight panel and currently plies his trade at Holland & Knight, has a reputation as one of most principled and savvy politicians around. He has a few pointers for new members of Congress. After all, there are rookie mistakes, and there are rookie mistakes on the national stage, with consequences for constituents — and maybe your next election.