BY REVEALING the names of some of the people who will serve in his administration, Mayor-elect Marion Barry yesterday gave the city the first hard evidence of how he plans to run his government. From all appearances, it's an encouraging beginning. To start with, Elijah B. Rogers, appointed to the No. 2 position in City Hall -- City administrator -- comes with high marks from public-management professionals throughout the country. The choice of Mr. Rogers, who has been city manager of Berkeley, Calif., should expand the city administrator's role from being simply a political adviser to being a technical manager, as the job was intended to be -- and should be.

Mr. Barry also will change the structure of the executive branch by creating five assistant city administrators to oversee and coordinate the work of the city's various departments and agencies. Heaven knows that closer oversight by skilled management experts is sorely needed. Only time will tell how well this new arrangement will work. But in making these selections, Mr. Barry has chosen an interesting combination of talents. Some, such as Gladys Mack and Judith Rogers, have worked for Mayor Walter Washington; they will bring years of experience and sound judgement to the Barry administration. Others, such as Colin Walters, Carroll Harvey and James Gibson, have already worked with Mr. Barry, either on his campaign or as members of his transition effort.

Mr. Barry has appointed only two department heads so far. But while all the agency posts are important, he was right not to waste any time announcing a housing director; Robert L. Moore, from Houston, has solid credentials in the field. George Harrod, who has a clear understanding of the city's complex personnel regulations, is a logical choice to continue as the personnel director.

Appointing city officials, of course, is only a first step. Making good on campaign promises is the hard part. And already, Mr. Barry's transition task forces have given him a taste of just how hard it will be to make the city's sluggish bureaucracy move in the "Compassionate and competent" way he wants it to. In more than 2,000 pages of impressive reasearch, his transition team has pointed out that the city is financially strong but administratively weak. So it's not just a lack of money, though that has been the complaint from City Hall for too long. Instead, something approaching wizardry with civil-service and prsonnel rules will be needed to make the machinery hum.

Marion Barry claims that he will be able to do this. To the extent that he succeeds in precisely this undramatic and complicated endeavor, he will be able to bring about the significant improvements that local government in the capital city so urgently needs.