How to Write a Certificate of Appreciation Using Concise, Grateful Language
The writing, or wording really (because this language will most-likely be printed on the document whether you have it custom-made by a printer or do it yourself), will differ to some degree depending upon the rationale behind it. However, you will mostly see some of the same universal language on one of these. Words such as “For outstanding service to", “In recognition of commitment to a standard of excellence", or “In recognition of ______’s outstanding contribution to _____" would be appropriate for your purposes.
Perhaps more formal verbiage such as “Be it known that upon the recommendation of title and name of official giving the award, the recipient is hereby honored with the utmost gratitude for their selfless service/ loyalty/excellence to the company/organization." The easiest, no frills document would simply have the title Certificate of Appreciation in a larger font near the center mass. And under that, This Certificate is awarded to Name of Recipient and under that, in recognition of valuable contributions. Then the presenter just signs and dates it at the bottom. That exact certificate is provided in the other article mentioned above.
Awards for employee of the month, worthy contribution to a project, outstanding student, and many more, all fall under the umbrella of an award of this type and are also straightforward wording. Other keywords such as teamwork, dedication, outstanding vision, talent, commitment of time, support, and inspiration, might be in order for your purposes too.
The bottom line is to use writing that reflects how much that award winner means to the person, company, or organization that feels the need to present it. Along the same lines as this project would be the need to write a recommendation letter for a deserving person who asks you for it. We’ve got you covered there too. Read Personal Reference Letter of Recommendation Tutorial to learn all about that. But as far as the project we outlined here, just make the certificate reflect genuine sincerity and thankfulness, and you will achieve the purpose of giving credit where credit is due.