Q. Since I work only part time, summer seems like a good time to help my children learn more. But if last year is any example (and the one before), the time will be frittered away. Can you make any suggestions?

A. The Home and School Institute, a 7-year-old, nonprofit organization, helps parents and teachers work together to tease a child's mind - and with good success. Achievement scores in reading have risen when these techniques have been used.

The HSI stresses the need to talk with a child, to be specific, to instill competence - and thereby self-esteem - and they give enough examples that at least some of the 5-, 10-, and 20- minute activities should suit your household. All of them use the small tools and basic supplies found in very home.

Some of this information is given in teacher workshops around the country, some in books, but starting next week parents are in luck. The HSI is compressing much of its knowledge into four evening classes for parents at the Rockville campus of Montgomery College. The course, "Help Your Child Achieve," runs from 7:30 -9:30 p.m., June 19, 21, 26 and 28, at a cost of $20, plus $10 for books. The college, 762-6088, or the institute, 466-3633, can give you more information.

If you can't make the classes, the institute will send you background material, or for a 5--cent handling charge, a sample of their past advisories which contain many tips. Both require stamped, self-addressed envelopes.

The institute also publishes three books to guide parents: "A Family Affair: Education," for $8, which outlines training strategy and techniques that work well with children; "The Three Rs Plus," $9, which shows how much self-esteem depends upon ability and how to improve both, and "101 Activities," $6.25, designed to help parents better carry out the philosophy of the school. All have a $1.50 handling charge.

Orders and queries should be sent to the institute, c/o Trinity College, Washington, D.C. 20017.

Q. Quick! We are here for the summer from Ausin, Tex., while my husband works on a government grant. Out children - 7, 9 and 12 - want to see everything.

We have been to the monuments, the Capitol and some of the Smithsonian buildings, but I'm sure there are many places that Washington families know about which we would love to see. How can I find out what they are? I hate to say it, but museums are beginning to pall.

A. The ninth edition of the super book, "Going Places With Children in Washington," has just been released.Revised every two to four years, each edition explains why 150,000 copies have been sold.

Its excellence reflects the sound learning-by-doing approach of its publishers, Green Acres School in Rockville, Md., as well as the insights of the parents who have written the book.

You find out the hours, charges and focus of more than 400 places in town (and a few in Baltimore and Annapolis), and not just museums, but theaters and festivals, gardens, farms and amusement parks. You discover how to get tickets for the sunset parade at the Marine Barracks - a memorable sight at any age - where to get the best hobby supplies and which restaurants are cheap enough to take the children.

It's $4.95 at all bookstores, and certainly worth it.