举个例子，我们可以说：We're very happy to have client like you, you are very warm and pleasure to deal with.
或者我们也可以说：It has been enriching for us to have had you as our valued client.
或者可以这样说的更长一点：Thanks for all your support and your valuable interaction in 2021. We hope for a lot of many fruitful interaction in 2022.
对于关系比较好的客户，我们可以说：We are so grateful for not only your continued partnership, but for your friendship, and we look forward to working together with you in the new year.
简短一点，我们可以这样说：May you take your business to new height in the new year,.
或者我们可以说：Wishing you the best opportunity to grow and write the new successful story.
或者：On the special occasion of the Chinese new year, we wish you the best of successing growth, prosperity and achievements.