No. 1 Goal Weighs on Teen-Ager’s Mind : Tennis: Conchita Martinez, 17, turns to a new coach, new tactics and a limited schedule.

How do you get to be No. 1?

For 17-year-old Conchita Martinez of Spain, you change coaches, alter your game, limit the number of tournaments you play and try to live up to some staggering potential.

There is already a fairly glowing consensus of Martinez in her peer group.

--Said Martina Navratilova: “She has got a chance to be one of the best, if not the best.”

--Said Hana Mandlikova: “She’s so young, she has lots of time to improve and she’s very good already.”

--Said Pam Shriver: “Conchita Martinez is going to make people worry for a long, long time.”

Four months younger than countrywoman Arantxa Sanchez, Martinez was more highly regarded until Sanchez won the French Open last June. Martinez went from No. 40 in the singles rankings to the top 10 with a 34-9 record in 1989.

“We are not good friends, but we are friends,” Martinez said of Sanchez. “I am happy that she won the French Open. Maybe the people say I’m better player and I have better game, but she has one Grand Slam.”

Martinez, seeded second behind Navratilova, makes her 1990 tournament debut in the $350,000 Virginia Slims of Indian Wells which begins today at Hyatt Grand Champions.

Eduardo Osta, who replaced Eric Van Harpen as Martinez’s coach in January, said he is trying to install more of an all-court game for 1990. While clay remains Martinez’s best surface, she believes it is vital to develop serve-and-volley hard-court tactics.

“You have to learn,” she said. “To be No. 1, now I start to serve and the volley and come to the net. You have to work on everything.”

Osta, who quit the men’s tour to work with Martinez, plans to follow Harpen’s lead and keep the number of tournaments Martinez plays to 14 or 15. She played 12 last year and won three.

The idea is to work on her game with practice instead of trying to work while playing tournaments, Osta said.

“We don’t need to play too many tournaments because we need to practice and learn a more complete game,” he said. “You cannot play each week. That’s no way to learn.”

However, such a strategy has its critics. Mandlikova went so far as to add a postscript to her praise of Martinez by saying she wished Martinez would play more tournaments.

Mike Estep, who has coached Navratilova and Mandlikova, questioned the motive behind a limited playing schedule.

“A lot of people are just playing the computer,” Estep said. “They’re reducing their schedule to the majors and a few others, which are worth more computer points. That way, you don’t put your computer points in jeopardy and you protect your ranking.

“I know Conchita never plays too much, but I just assumed she was coming along slowly. That probably wasn’t a correct assumption.”

Osta defended Martinez’s scheduling and said it is vital to her development at this stage in her career.

“Maybe in two years it will be too late,” he said. “Better to start now. We start to play tournaments now, so we’ll see. The No. 1 position, it’s very difficult to see, but there are four for five girls with a chance and Conchita is one of them.”

Some aspects of Martinez’s game are already in place. While her forehand isn’t as well known as that belonging to Steffi Graf, Martinez can still hit with a great deal of pace. Osta ranked Martinez’s forehand second only to Graf’s in the women’s game.

“She can win points with her forehand,” Osta said. “She has to learn to win points with the other shots.”

Martinez has stayed away from the grass at Wimbledon, but last year she reached the quarterfinals of the French Open and the fourth round of the U.S. Open.

Many expect Martinez to go even higher, possibly to No. 1. Can this be the beginning of her reign in Spain?

“We see,” Martinez said. “I cannot say how far I am going to be. I just try to play the best. Maybe I feel the pressure a little bit, but I have to forget it and try to play only tennis.”