From Wikipedia:
Deaver worked primarily on media management forming how the public perceived Reagan, sometimes by engineering press events so that the White House set the networks' agenda for covering the president.
It was argued by some - click here for the argument - that the Reagan White House was more interested in visuals than commentary because "nobody heard what you said."
From his obituary in the Guardian:
His characteristic gesture was to hold up two joined hands, the thumbs pointing downward, to simulate the framing of a television image or still photograph. One contribution he made to Reagan's triumphs was his gift for choosing the pictures behind Reagan's head. Deaver said as much himself. "I've always said the only thing I did is light him well," he told the Los Angeles Times in 2001. "My job was filling up the space around the head. I didn't make Ronald Reagan. Ronald Reagan made me."
His most brilliant single idea was to place Reagan, in Normandy for the 50th anniversary of D-day, on the clifftop above Omaha beach where some of the US invasion forces had disembarked, in 1944. There Reagan talked to an American woman whose father had died in battle. Less successful was his choice of a military cemetery at Bitburg, Germany. Reagan was supposed to greet the West German chancellor, Helmut Kohl, but Deaver's planning had slipped up. Forty-nine members of the Waffen SS are buried there.
Here's his obituary in the Washington Post.
Here are samples of his work: