Often the most simple words are the most meaningful. All too often we get so wrapped up in what we are doing to move the business forward we forget to consider the considerable contributions of all of the people around us.
Considerable contributions does not necessarily mean large contributions. What it means, is that in some meaningful way, the people were involved in our achievements and we would have not been as successful had they not been involved.
No one can be successful in a vacuum. You cannot achieve anything meaningful without the help of other people. While you may be the person who gets the attention, I assure you your efforts are not the only individual efforts that contributed to your achievements. Many other people helped you. (From the doctors and nurse who aided in your delivery, to your teachers and your friends who gave you advice, even when you didn't want it.)
Take the time to look around and consider where you would be if you didn't have other people helping you. You may subconsciuosly look to they that set fine examples by what they do well, and you follow their lead. You may learn from the mistakes others have made, because indirectly they paid a price you didn't have to. All of these people deserve your thanks.
One of the best means to say thanks to those people who helped and may not be around anymore, is to make the best of what you have because of the opportunities you have been given. Of course the very best way to say thank you is to simply say; "thank you, I really appreciate what you have done for me."