Start with treatment. Congratulations to the families and friends begin with "dear", "beloved". These epithets can be used, if the warm relations among colleagues, but against principalities, or if the card is written on behalf of several employees it is better to choose "dear" and sometimes "the honourable". Greetings for friends, you can use a partial name or even a nickname, of course, if it is not offensive.
Specify what kind of celebration you congratulate the person. If writing postcards timed to the anniversary, don't hesitate to write a number, but if you congratulate a woman think if she's happy. Of course, you should not write "we congratulate our friend with a 39-year anniversary".
Use the congratulatory texts that you can find on the Internet. As a rule, they are presented in the poems. Specialized sites have convenient search system greeting and the recipient wishes.
Write a text of congratulations from the heart, after all, sincere words are particularly valuable. First practice on the first draft, eliminate the tautology, try to pick up the synonyms to the text is clearly readable. If you write poems, don't be afraid that they will get a little sloppy, most importantly, that they contain genuine feelings. Keep in mind the nature and age of the person, which wishes. The signature must match the style of the text such as "your loving daughter", but not to recall the words from the funeral wreaths.
Purchase a suitable occasion card. A ready card already have the typographical text, poems and wishes. You can complement it with a few words and put his signature. This is ideal if the card is given away on behalf of several people. In this case everyone can write wishes on the sidelines and put your signature or initials.
I full name (no middle name), if you congratulate a colleague at work, employees of establishments where you are, for example, a kindergarten teacher, a local official. You can also specify the name and initials.
Use your nick that you registered with on the forums, in magazines or other Internet resources. Appropriate, if you are writing a congratulation active user of these sites, messages for grandpa's better to use something more traditional. Try to mimic the font and tilt of the text below the signature was similar to the way nick is written in a specific online resource.
Put in the bottom of the postcard the date. Many people have received postcards all my life, it will be easier to remember later in what year were written these words.