Elizabeth Dole's White House office looked as if it were opening night yesterday, filled with bouquets, flowers, balloons and champagne. "Isn't this something?" she said in her North Carolina lilt. "Don't you like the one with the yellow back there? Isn't it cute, the one with the oriental look? And that's a pretty one, I think. And this was really sweet, this is from one of my attorney advisers at the Federal Trade Commission, who hasn't forgotten me after all this time. That was so thoughtful of him, really, to do that. Did you see this one? I love this. Oh, it's beginning to look a little droopy already. But look at all those little pretty things. And the colors are so nice."

She was sweet, earnest and immaculately dressed in white. "I think life is what you put into it," she said, bright-eyed. "When something negative happens, I try to look at that as a growing experience."

Doesn't she ever get depressed? Is she always so cheerful?

"Yeah," says her husband, Sen. Robert J. Dole (R-Kan.). "It's frightening."

On Wednesday, President Reagan brought Elizabeth Dole, 46, into the White House East Room and announced on live television that he was nominating her to be his secretary of transportation. That makes her the second woman in the Cabinet, joining U.N. Ambassador Jeane J. Kirkpatrick. Dole looked a little nervous, but yesterday she was chipper. She won't talk about her plans for DOT, but she did say she wants to do something about drunk driving. Meanwhile, "I love what I'm doing," she says. "So it's a bittersweet feeling to leave." As the president's assistant for public liaison to special interest groups, Dole listened to the complaints--and there were a lot--of women, blacks, veterans, the handicapped, Indians, business leaders, farmers and more. She took a lot of abuse, but found few inside people willing to listen to her. "I'd despise that job," says one White House staffer.

Not Elizabeth Dole.

"She doesn't throw things," says her husband. "She doesn't get really mad. She gets a little distressed sometimes--like, 'Why am I doing this?' But that's it. Pretty soon, she's off chirping away on something else.

"She's a perfectionist," he adds. "She takes notes on everything. If somebody called to sell her a magazine, she'd take notes on that. She also makes little lists: Tomorrow I'm going to do A-B-C-D-E-F-G. And she reads that book called 'The Time Trap' about every other week . . . She reads everything. I keep telling her, 'You're not the president.' "

She's not even close. Cut out of the "inner loop," which is White House jargon for the staff power center, Dole says, "Let's face it. There's the Big Three, and the rest of us are more or less in and out."

She gets mixed reviews. White House chief of staff James Baker praises her as "an extraordinarily competent person;" others say she has a hard time setting priorities. Still others are highly critical, saying she overdid her research--yet could have done more to help develop constituencies for Reagan's policies.

"There's probably something in me somewhere that would like to be liberated in terms of not having to meet all these deadlines, and do your best, and all those sorts of things," she says. "But I'm so used to me, with my way of doing things, that I guess I'm just adjusted to being fairly disciplined."

Unlike a number of women at high levels in politics, Elizabeth Dole hides her toughness behind a feminine, almost girlish manner. Her hair is always perfectly styled, her nails nicely manicured, her manners gracious. Yesterday, she excused herself to make a "pit stop" before her picture was taken, and then fussed with the jacket of her white business suit. "It just won't behave," she fretted.

She grew up in Salisbury, N.C., the daughter of a well-to-do floral products importer. She ran for president of the third grade, went to Duke University, was elected May Queen, graduated from Harvard law school, worked briefly as a lawyer, was deputy director of the White House Office of Consumer Affairs in the Nixon administration, then became a federal trade commissioner. Her 1983 New Year's resolution is to get home at 7 p.m. so she can watch the news while she does a half-hour of exercises.

"She was never pleased if she got a low mark in school," says her mother, Mrs. John V. Hanford. ("Please don't call me Mary Hanford," she says. "It sounds like you're divorced." She is widowed.)

"She was always conscientious and dutiful," says her brother, John Hanford Jr. "Her parents motivated her. The theme was generally that you should do your best in any circumstance. Nothing unusual about that, except that she was frequently reminded of it."

Elizabeth Hanford met Robert Dole, then chairman of the Republican Party, in 1972. She was in the White House consumer office at the time, and wanted a consumer plank in the Republican platform. "I even remember what I had on that day, for some reason," she says. "He walked into his office, we were already there, and I looked up at him, and I thought, 'Goodness, he's an attractive man.' "

"I don't recall much about the plank," says her husband, "but I did recall Elizabeth." He wrote her name on his blotter, and then did what any Washington political male would have done: Nothing.

Months later, they talked to each other at the 1972 Republican National Convention in Miami. "And then about a month after that," she says, "he called one night. We talked for about 40 minutes. And it was a wonderful conversation. We just seemed to be on the same wavelength, all these mutual interests, lots to talk about. And so at the end of the conversation, he said, 'Well, I've enjoyed visiting with you.' And he hung up.

"So then about two or three weeks later he called again. And we had another really nice conversation. And that was a long visit, too. And he said, 'Well, maybe some time we could have dinner. And I said, 'Fine, I'd enjoy that.' And he hung up.

"The third time he called, he did ask me out to dinner. But you know, there was something about that I liked, I have to admit. He was a little shy, and I liked that." They were married in 1975.

Dole, chairman of the Senate Finance Committee, has in the past been a loud critic of Reagan's economic program. Elizabeth Dole, whose job is, in part, to sell that program to America's interest groups, insists there's no problem. "I think he's worked very closely with the White House," she says. "But I don't think that anyone could expect him to march in lock step.

"For instance, if there's something that's being discussed in here that's not ready to go to Capitol Hill, what do I do? Do I talk to him about it or what? But both of us are able to compartmentalize, to set aside those things that shouldn't be discussed with each other. It's really not that difficult. He told me when the Gang of 17 was meeting the bipartisan group of administration officials and congressional leaders who tried for a compromise on the 1983 budget , 'Elizabeth, we've decided that this should be confidential, and I just won't be able to talk to you about it. And I said, 'Fine, no problem.' "

But some staffers still say it was awkward--as was her husband's recent behavior suggesting he might be a Republican presidential candidate. "Somebody said to me that 'This signals that the president's running,' " says Robert Dole. "I don't view it as anything except a good appointment. 'Excellent choice,' as I said in my two-word news release."

Does Elizabeth Dole think her husband will run for president?

"He's not told his wife," she responds.

"One of the things we really share is our enjoyment of each other's experiences in our jobs," she says. "It's a great way of sharing, even if you can't share all the information, and you don't have as much time together, when you are together, there's so much to talk about. And you share a pride in each other's accomplishments. There's something there that's very special when you have dual careeers.

"When I first came into this job, I thought, 'Oh, isn't this great, there's this wonderful source of information. Because so many of the issues I'm dealing with Bob is into. The Caribbean Basin initiatives, and Social Security, and all these things that he has. Well, I learned very quickly that that is not a very healthy thing. If you get home at 8 or 9 at night, and start pumping your husband with 10 questions on what did you do on this, and how do you mean you're going to change it, and you have all these things you want to know, he has no chance at all to get away from the pressures of the office and just relax. And if he were doing that with me, saying 'What's the president going to do?' it just doesn't work well that way. So very early on, I told Max Friedersdorf the former White House congressional liaison , 'Bob Dole is your jurisdiction, not mine.' "

Already, the Doles are being branded the "The Second Most Powerful Couple in Washington." Elizabeth Dole laughs, just a little grimly. "We both need the time away from it," she says. "And we sort of set Sundays aside as a day that we are involved in church things."

Elizabeth Dole, who also takes notes of the jokes in the minister's sermon, says her husband is not quite as enthusiastic a churchgoer as she is. But she doesn't allow him to stay home to watch the Sunday morning interview shows, "because we have a machine that will tape them."

"But if he's on one of them," she says with a sweet show of who's boss, "then he's excused."