Montgomery County Executive Marc Elrich, who squeaked past businessman David Blair to win the Democratic primary in Maryland’s most populous county after a recount, had one main takeaway from his razor-thin victory: He has to do a better job communicating. Elrich, who clinched the nomination this week by 32 votes, in an interview Friday pledged to redouble efforts waylaid by the pandemic in key areas such as affordable housing, transit and health equity. He blamed the close race with Blair on negative ads and on voters not being fully aware of some of the actions he’s taken over the past four years.