Maryland Gov. William Donald Schaefer officially began his reelection campaign yesterday, but it wasn't easy to tell.

There was plenty of music, "Maryland, My Maryland" and "The Star-Spangled Banner" in brassy arrangements. Then a slide show, a sentimental montage of Schaefer being a pal to schoolchildren or strolling near the water.

Then Schaefer himself, at his extemporaneous best, barely mentioning the subject at hand. "This is where in the script it says I announce my candidacy, so here today in Langley Park I announce my candidacy," Schaefer told an audience of local politicians, schoolchildren and parents at the Langley Park-McCormick Elementary School in Prince George's County.

Facing no announced opposition in the September Democratic primary, and a little-known Republican as his likely opponent in the general election in November, Schaefer's kickoff ceremonies around the state yesterday were hardly standard reelection fare. He played down his political plans in favor of his newfound "Campaign for Maryland," an effort to encourage citizen activism that will be coordinated by his reelection team.

Campaign aides say this unusual theme, aimed at encouraging Marylanders to donate their time to improve education and the environment and fight the drug problem, is an example of the popular governor's "positive politics."

But they also hope to make Schaefer the politician indistinguishable from Schaefer the civic booster, and convince people that voting for the incumbent is also a way to help their community.

"It is very much a political process, an effort to energize people," said campaign manager Jim Smith, who said it was his idea to put a civic veneer on the effort to reelect Schaefer and his running mate, Lt. Gov. Melvin A. Steinberg.

The ceremonies yesterday in Langley Park and Baltimore portrayed the 68-year-old Schaefer as above the fray, looking to use more than $1 million he has raised in campaign funds to help the state's citizens.

Schaefer, who is limited to two terms under the state Constitution, never mentioned the only other announced gubernatorial candidate, Republican William Shephard, a lawyer and former Foreign Service officer from Montgomery County. And the slide show, which will be shown around the state as part of the volunteer effort, even uses the head of Shephard's party, President Bush, in a picture with Schaefer.

Shephard said he thought the upbeat mood of Schaefer's announcement should not obscure the governor's unwillingness so far to commit to any debates.

"I am told this was a media glitz. Fine. I love a parade," Shephard said. "Frankly, I have been seeing discontent all over the place . . . . What you ought to do is debate the issues and give people a good solid base for judgment."

Schaefer enters the race from a position of strength. Although his relations with some legislative leaders have been rocky, his first term produced results, most notably approval of a new sports stadium in Baltimore, a new light rail line and a landmark law preventing the sale of some cheap handguns.

Still, he has to mend some fences. Organized labor and the Maryland State Teachers' Association have been at odds with some of his recent decisions. He has suffered criticism as well for cost overruns on large projects and has hinted he would seek a tax increase in a second term to finance more programs.

But, according to aides, Schaefer has enjoyed consistently high approval ratings in preliminary polls.

With a surplus of campaign funds and the desire to carry a strong mandate into a second term, Schaefer will be working closely to help other Democrats, according to campaign aides. As the political race progresses, for example, Smith said he expects the "Campaign for Maryland" literature to begin bearing the names of dozens of other Democratic contenders who have signed on to help the volunteer effort and their own election chances.

After his appearances in the Washington suburbs and Baltimore yesterday, Schaefer also planned an announcement in Ocean City last night. This region-to-region scheduling reflects what Schaefer said in his announcement is an effort to broaden his base since ending his 15-year term as mayor of Baltimore and becoming governor of Maryland.

His first gubernatorial campaign was announced from the Baltimore row house that Schaefer occupied for most of his life. Entering what will likely be the last campaign of his 30 years in politics, his first stop yesterday was at an urban elementary school in Prince George's that is trying to devise ways to teach and unify an ethnically diverse student body.

Like the basic theme of the campaign, even the site had a double meaning. It was politically significant for Schaefer because most of his opposition in the 1986 race and in the state legislature has come from the Washington suburbs, where he has failed to fully overcome his image as a governor mainly interested in helping Baltimore.

But it was also picked as an example of the type of volunteer program Schaefer will encourage in the coming months. In this case, local businesses are helping the school; at the noon announcement in Baltimore, he was addressing members of Project RAISE, a mentor program that teams youths with an adult for guidance beginning in the sixth grade.

At the events yesterday, campaign aides distributed packets with Campaign for Maryland sign-up cards, all printed by the Schaefer reelection committee.

The packets included a 32-page guide to alcohol and drug abuse prevention programs around the state. Guides on environmental and education programs also are being printed. Specific tips for prospective volunteers include serving non-alcoholic cocktails at parties, visiting boarder babies at local hospitals or becoming a reading tutor.

Patrice M. Cromwell, a management consultant recruited to establish volunteer organizations in every jurisdiction, said the activities could even be as simple as using less water in the dishwasher. Citizens will even be able to dial a toll-free number if they want to receive a free "volunteer kit" from the campaign.

None of the materials distributed yesterday mention the Sept. 11 primary or the Nov. 6 general election. They carry the Schaefer/Steinberg logo and, using Schaefer's pet phrase, exhort voters to "Do It Now."