To laugh often and much;
To win the respect of intelligent people and the affection of children;
To earn the appreciation of honest critics and endure the betrayal of false friends;
To appreciate beauty, to find the best in others;
To leave the world a bit better, whether by a healthy child, a garden patch or a redeemed social condition;
To know even one life has breathed easier because you have lived.
This is to have succeeded.

Although this is often attributed to Ralph Waldo Emerson, it is unlikely that he is the source of this work (and it doesn't sound like his poetry either).

First off, none of the word sequences appear in any of Emerson's works. It is possible to search for them at http://www.emersoncentral.com/search.htm, and your result will be the same as mine - nothing (though, if you search the web, you will find dozens of references to it attributing it to Emerson. I even found this quote on a card.).

There is evidence that this dates back to 1905 by Bessie Stanley with the poem:

He has achieved success who has lived well,
  laughed often and loved much;
who has enjoyed the trust of pure women,
the respect of intelligent men and the love of little children;
who has filled his niche and accomplished his task;
who has left the world better than he found it,
  whether by an improved poppy, a perfect poem, or a rescued soul;
who has never lacked appreciation of earth's beauty
  or failed to express it;
who has always looked for the best in others
  and given them the best he had;
whose life was an inspiration;
whose memory is a benediction.

It was submitted to the Brown Book Magazine in a contest in 1904 and was awarded a $250 cash prize.

However, even the printings of two local newspapers in 1905 with that poem do not agree (the one above is from the 1937 edition of Bartlett's Familiar Quotations. There is some suspicion that this is a paraphrasing of a previous quote from Robert Louis Stevenson, however this was published several years after his death (1894).

Our business in life is not to succeed, but to continue to fail in good spirits.

Whatever the case, and whoever wrote it - the ideas and feelings that it speak of are still as powerful as ever.