Sharon Tarlton, her husband and three young children live in Millville, a small town in southern New Jersey. With an income under $20,000 a year, the Tarltons are doing some of what a great many other American families are to cope with inflation.

"We can't get the things that we need for the house and kids," Mrs. Tarlton told an interviewer for the Washington Post-ABC News poll, "so I make more clothes than I used to -- almost all the girls' clothes."

That is just the beginning. To save on expenses, the Tarltons spend as much as their free time as possible at home. Mrs. Tarlton shops at secondhand stores, and her husband repairs items that would have been thrown out had they broken down a few years ago.

The Tarltons are spending more of their money on food and buying less liquor and beer these days. To what Mrs. Tarlton describes as the maximum extent possible, the family has cut back on medical and dental checkups and on donations to charity. Because of the cost, the Tarltons didn't go away on vacation last summer and they don't plan to travel this summer, either.

Since her family is making such accommodations, Mrs. Tarlton told a Post-ABC interviewer, they are eating as well as they have in the past. Moreover, they don't buy anything with credit cards and are able to meet their monthly bills with no real problems.

The Tarltons represent just one household trying to do it best in difficult financial times. Multiply that by about 50 million or 60 million households and you have a picture of what is taking place in the United States today: for approximately 75 percent of the American people, the year 1981 is one of more than national belt-tightening. Rather, people are becoming accustomed to making a great number of small changes in the way they live because of inflation.

For some, the changes are more than small ones. The Washington Post-ABC News poll interviewed 1,206 people nationwide from March 25 to March 29, asking a wide array of questions about changes in lifestyle. Overall, 20 percent of those interviewed, a figure equivalent to 30 million adults, appear to be living under severe strain. Many are taking second jobs, skipping meals and selling possessions such as automobiles that they cannot afford.

A much larger group, about 55 percent, are feeling the pinch but not as severely. And a remaining group of some 25 percent seem to be inflation-proof and thriving.

In all, 37 percent of those interviewed said that in the past few years they have had to go deeper into debt simply to make ends meet, and 42 percent said they have felt it necessary to take more overtime work. About a quarter of those near retirement age say they have had to postpone their plans and continue working.

A 29-year-old Wisconsin crop consultant says the main effect of inflation on his family has been to alter their diet; "We aren't eating as much pork and beef, and we eat more hamburger and fish. We also eat more vegetables, which come from my garden, which I started because of inflation."

But that is only one of the changes that he, his wife and young child have made. According to his account, they have moved to less expensive housing, have stopped buying clothing the way they used to, are cutting back on the barber shop and beauty parlor and, to some extent, are giving up hobbies and sports that cost money. They are entertaining less and, whenever possible, using coupons at the supermarket to lower their food bill.

The cutbacks made by this Wisconsin family and the Tarltons in New Jersey are common. One series of questions by the Post-ABC News interviewers went like this: "I am going to read some changes that some people say they have made in their lives to deal with inflation. As I read each one, please tell me whether during the last few years you have found yourself making the change mentioned or not." Following are some of the specific questions, and the percentage of people who say they have made that change:

Minimizing use of electricity: 87%

Spending your free time at home instead of going out: 76%

Cutting back on gifts: 72%

Repairing things normally thrown out: 70%

Not buying clothes the way you used to: 69%

Entertaining less: 63%

Eating less red meat: 57%

Using less prepared and frozen food: 57%

Giving up hobbies or sports which cost money: 56%

Cutting back on charities: 55% Postponing medical or dental checkups: 41%

These kinds of cutbacks are being made by people in all income groups, but, quite naturally, they are pronounced among the less affluent, and especially among black Americans. One in seven blacks interviewed, for example, said there are months when they just cannot pay their household bills. Only one in 20 white reported such hardship.

A total of 1,206 people nationwide were interviewed by telephone March 25 to March 29 in the Washington Post-ABC News poll on how Americans are coping with inflation. Theoretically, figures based on that number of interviews are subject to a sampling error of about 3 percent in either direction, 95 percent of the time.

The latest available U.S. Census Bureau figures on age, sex, education and race were used to adjust the sample slightly so that it matches the overall population in those characteristics.

An article in yesterday's Washington Post relating to other findings from the same poll incorrectly stated that 1,305 people were interviewed rather than 1,206. For statistical purposes, the change makes virtually no difference in the reliability of the poll's findings.