`Dear Aunt Sophrona, thank you for the purple mittens ...'

ONCE you've tried on the clothes, built something with the put-together toys, hugged the teddy bear, and listened to the albums (OK, twice), it's time to write your thank-yous. Are those groans we hear? You say you hate writing thank-yous; don't have any stationery; don't know what to say; can't remember your Aunt Sophrona anyway and thought her present was great for someone about 30 years younger (or older) than you?

We don't like to get involved in other people's squabbles, but we would like to point out that anyone who's gone to some trouble to get you a present deserves a thank you. Your note of gratitude gives them something nice in return - something they'll probably remember next year at gift-giving time.

First, you'll need supplies. See if you can find some stationery; if you really haven't got any, you can use your school paper. Maybe you'd like to decorate it first - draw a little picture at the top, or use stickers, if you like. Now you need a writing instrument. Technically, it should be done in pen (one of those erasable pens would be great). If you have a good dictionary, or a patient relative nearby who's a good speller, you should be able to pull it off in non-erasable pen if you ask a lot of questions. If you really don't think you can manage a pen, Aunt Sophrona will be happier with a thank-you in pencil than no thank-you at all.

The last thing you need is a list of names and addresses of those on your thank-you list, plus some idea of what each one sent you. The rule here is to send a note to everyone you can't thank in person; however, you get lots of extra credit for thanking people you do see.

Got everything? Great. Here's what to write:

The Date: This goes in the upper right-hand corner. You can write it like you do in school (December 26, 1986), or put the holiday (New Year's Day, 1987), or the day (Saturday).

The Salutation: You address people in letters the same way you address them in person. So write Dear Aunt Sophrona (or Dear Mr. Biddy or Dear Grandma and Grandpa) at your left margin, a few inches down from the date. That line ends with a comma.

The Thank-you: Start by thanking them for their gift (that lets them know who sent it). Now comes the creative part - tell them why you like it. If it's useful, tell them what you'll use it for (I like this game because I can use it to beat my brother); if it's wearable, tell them how it fits and what it goes with (the mittens are warm, and they match my coat); if it's money, tell them how you plan to spend it (or save it). The object here is to find something nice to say about it, even if (and this is a big if) you don't like it. Is it an interesting color? If you hate the music, do you like the jacket cover? If it doesn't fit, is it at least warm? Or pretty? Does it have interesting pockets?

The Follow-Up: Here's the heart of the matter. Thank them for taking the time to get you a present. What you're really thanking them for is caring about you. You can say this in lots of different ways: ``Thanks for taking the time to find this toy''; ``It was so kind of you to knit this just for me''; ``I know you went to a lot of trouble to get the Pound Puppy''; ``Wasn't it kind of you to let me pick my own present with your generous check?''

The Ending: You can write Sincerely, or Very Truly Yours, or Love, or Your Nephew (Niece, Grandson, Neighbor, Student, etc.). Then sign your name - even if your parents wrote down the rest, you can do this part.

The Envelope: Your address goes on the back flap; theirs goes on the front, about in the middle and to the right. Leave enough room to get their names all on one line (Aunt Sally and Uncle Dave Gigglethorpe). Don't forget the stamp, in the upper right-hand corner.

There now, you're done. You can go back to playing with your presents.