Chinese new year falls on January 31 in 2014. It's customary to greet Chinese colleagues and business acquaintances with a new year greeting when you first meet or speak to them during the 15 days of the new year.
The most common greetings you'll hear are 新年快乐 (xin nian kuai le), 'happy new year' and 恭喜发财 (gong xi fa cai), 'congratulations on receiving riches and prosperity'.
Riches a recurrent theme in Chinese culture, especially around Chinese new year. Fortune-related greetings for businesses include 财源广进 (cai yuan guang jin), or 'may riches enter in huge volumes', and 生意興隆/生意兴隆 (sheng yi xing long), or 'may the business thrive greatly'. 年年有餘/年年有馀 (nian nian you yu), 'surpluses every year', as well as 马到成功 (ma dao cheng gong), 'instant success', are spot on both for businesses and individuals.
马到成功 is especially apt in the coming year of the horse, as the character for horse, 马, begins the greeting, but it can be used at any other time as well. There are business-oriented greetings which mention the specific year, such as 马年大吉 (ma nian da ji), 'great fortune in the year of the horse', and 马年行大運/马年行大运, 'great luck in the year of the horse'. Just substitute the underlined character with the appropriate animal of the year.
Beyond these traditional greetings are some which are more relevant to those working. 新年进步 (xin nian jin bu), which means 'making progress in the new year', 心想事成 (xin xiang shi cheng), 'may your wishes come true', and the simple 工作顺利 (gong zuo shun li), 'may your work go smoothly', will all be well received. 事业有成 (shi ye you cheng) 'success in what you're working on' and 平步青云 (ping bu qing yun), 'an easy path to a meteoric rise' are equally auspicious.
If you can't remember too many greetings, don't worry - a simple 'happy new year' is fine. The whole idea is to start off the year right, and it's traditional to hope for fortune, prosperity and success. Don't mention anything worrying, and you'll be fine. 万事如意 (wan shi ru yi), 'may all things be as you wish'!