"One thing you have to get used to around Washington is that if you're wrong about something, you have to admit it. The faster you admit it, the better off you are."

With that farewell homily, delivered to 12 aides and reporter yesterday over a breakfast of quail and cheese grits, outgoing Attorney General Griffin B. Bell listed some of his mistakes and some of his boss, President Carter.

"The president, I think, hasn't done enough to build up the presidency," said Bell. "The president can't spend his time on minutiae. The president has to deal with the big things" -- a course Bell said Carter had followed successfully in foreign policy.

"I think the president tried not to act like he was the president -- like, 'I'm just one of the boys,'" Bell said. "I think people didn't like that . . .

"It's not a matter of being aloof or distant. It's a matter of him prioritizing his work . . .

"I would have a whole lot more discipline myself if I were the president, and I think you see he's been coming to that in recent days."

Carter now is abandoning his initial anti-establishment stance, Bell said, adding that it is none too soon.

"You can't be on the outside, because the establishment -- seen or unseen -- is what runs things," Bell said.

" . . . When I came to Washington, I intended to get in with the folks who ran things around here. I've been doing that. I think the president's doing that now. I think you're going to see, by the time he finishes his reorganization , . . that the president has joined the establishment . . .

"I don't know if the president thinks he's getting with the establishment -- he'd probably deny it -- but I'm telling you it's happening."

As for Bell's own mistakes, he acknowledged that the administration has not markedly improved the nation's illegal-alien problem, and has managed only to start a moderization of the immigration service.

He also said that the antitrust and civil rights divisions of the department "tend to be elitist," not taking enough account of "other things going on in the government and in the economy."

But Bell's heaviest criticism was directed at Capitol Hill. If legislators refuse to move on the energy program when they return after Labor Day, Bell said, Carter will have to take on Congress.