Pence should try to make Trump look like a regular Republican for those conservatives who aren't on board, and hit Clinton on the usual emailghazis. Kaine should try to make Pence defend Trump's litany of gaffes, and expose Pence's extremism relating to women and gay rights. They both should try to make clear the differences in economic policies, but I don't see how "tax cuts for the rich" is a winner for Pence. They both have been pro-free trade in the past, and both are now on anti-trade tickets.
Both seem to be your typical experienced politicians who can slickly field debate questions and attacks. Probably won't change much in the race.