Q. "The more I hear about kids who can't read and teachers who can't pass some of the subjects they teach, I wonder how my own two children are going to do in school," writes a father in Takoma Park.

"What can parents do to make sure their children get a decent education? Jill is just 2 and Eric is 4, but I'm concerned for them already."

A. Probably the best thing you can do for a child is to assume that every teacher (like every parent) has some flaws -- sometimes quite a lot of them. Looking back over the public, private and parochial schools we've known, the ratio, we've found, runs like this: One teacher will be excellent, onw will be awful and two will be quite routine and immensely forgettable. In fact, it's probably the same ratio of competence you find in most offices, and even in your own neighborhood organizations.

It's dandy to expect -- and to look for -- the best teachers and counselors your children can get, but ultimately in school, as in most things, the buck stops -- and starts -- with you.

You may send your children to Sunday school every week for 10 years, but it's still your job to instill values. And whether you send your children to public schools or pay thousands of dollars in tuition, it's up to you to open the minds of your children before they start, and to keep them open. If you do, they can grow with the mediocre teachers -- even the awful ones -- as well as the best ones.

Everything you do with your children increases their understanding, but for most of us, this parenting business has so many facets we find everything can be done a little bit better. This in itself is another reminder that parenthood is one long lesson in humility -- in case you need any more proof.

You open Eric's mind by encouraging him to look up at the odd rooftops and gables in your turn-of-the-century neighborhood, or decipher the letters on a manhole cover. When a child learns to look for the unexpected, he will get a great deal more out of life.

Whenever you program another fact into a child's brain, you help to open another circuit. The earlier you do it -- and the more circuits you open -- the more curious, possibly smarter, that child will be.

The first time a child eats a spring roll, tastes a kiwi, smells a gardenia, or sees the Calder mobile undulating in the National Gallery will be engraved in his memory. No matter how deeply it gets buried, it becomes another point of comparison in his mind. To stretch a child's frame of reference is one of the most important challenges a parent has.

Learning to communicate is also important preparation, and it can't wait until first grade.

As parents, we help our children talk clearly, but once the ideas are fairly well understood, we may forget the job is just beginning. Now you have to replace an old word with a synonym whenever you can, using it in context so he can understand what you mean without even realizing he's learning something new.

When you ask Jill whether she wants to wear her red shorts or blue, she learns which color is which. And after she knows them well, you ask her whether she wants to wear her navy blue shorts or her royal blue ones. Her eyes can tell that the blues are different; she just doesn't know the words to say so.

You help a child talk in dozens of other ways too. You do it when you have your child go outside to draw huge pictures in the air with his arms -- as if the air itself were an easel -- and sometimes to play music when he uses his poster paints. It's such an effective backdrop the pictures may go from joyous to forbidding and back again, depending on the music that's played. f

For the same reason, you'll want your children to sculpt out of clay one time, play dough another and papier mache a third. The more a child can express himself creatively, the better he can get rid of his feelings when words won't do.

And for a first-class look at what parents can do to teach their children after they start school -- and a fine resource for summer learning -- write to The Home and School Institute for their new 126-page trade paperback, "Families Learning Together."

The nonprofit institute has published the book to show families a number of quick, easy (and free) ways to expand a child's mind. To get it, send a $12 tax-deductible check to the Institute, c/o Trinity College, Washington D.C. 20017. Or to get some sample recipes for learning, send $2 and a stamped, self-addressed business-size envelope.

It's true: There may be some bad teachers (and there are), but even the best aren't as good as a parent who cares. That's why it's up to you to accept so much responsibility.

The Maryland Developmental Disabilities Council has published "Looking Forward," a free guide for parents of disabled children. Written by Cheryl Mowll and Ann Wicke, it's one of the best. To get a copy, write the Maryland State Planning Council on Developmental Disabilities, 201 W. Preston St., Baltimore Md. 21201.