Mr. Trump will try to hold her accountable for security lapses at the American consulate in Benghazi, Libya, and for the death of Ambassador J. Christopher Stevens there.

And he intends to portray Mrs. Clinton as fundamentally corrupt, invoking everything from her cattle futures trades in the late 1970s to the federal investigation into her email practices as secretary of state.

Drawing on psychological warfare tactics that Mr. Trump used to defeat "Lyin' Ted" Cruz, "Little Marco" Rubio and "Low-Energy" Jeb Bush in the Republican primaries, the Trump campaign is mapping out character attacks on the Clintons to try to increase their negative poll ratings and bait them into making political mistakes, according to interviews with Mr. Trump and his advisers.