Although an extremely popular Chinese New Year dish in Singapore, not many really knows the "correct" procedure of the Lou Hei? A quick "google" reveals some published sources, one which I believe should be politically correct, since it comes from the National Library Board.
I quote from the website:
Yusheng is deemed auspicious because of its homonymic quality - yu means "fish" but enunciated appropriately, it also means "abundance", while sheng literally means "raw" but enunciated appropriately, it means "life". Thus Yusheng implies "abundance of wealth and long life". In Cantonese, it is known as lo sheng with lo also meaning "tossing up good fortune". The tossing action is called lo hei, which means to "rise" (hei), again a reference to a thriving business and thus its popularity with businessmen during the New Year.
All at the table offer New Year greetings.
Words: Gong xi fa cai （恭喜发财） meaning "congratulations for your wealth" or wan shi ru yi （万事如意） meaning "may all your wishes be fulfilled".
Fish, symbolising abundance or excess through the year, is added.
Words: Nian nian you yu （年年有余） and you yu you sheng （有余有生）.
The pomelo is added over the fish, adding both luck and auspicious value.
Words: Da ji da li. （大吉大利）
Pepper is then dashed over the ingredients in the hope of attracting more money and valuables.
Words: Zhao cai jin bao. （招财进宝）
Then oil is poured, circling the ingredients to increase all profits 10,000 times and to encourage money to flow in from all directions.
Words: Yi ben wan li （一本万利） and cai yuan guang jin （财源广进）.
Carrots are added to the fish, indicating blessings of good luck.
Words: Hong yun dang tou. （红运当头）
Then the shredded green radish is placed on the fish, symbolising eternal youth.
Words: Qing chun chang zhu. （青春常住）
Next, the shredded white radish is added for prosperity in business and promotion at work.
Words: Feng sheng shui qi （风声水气） and bu bu gao sheng （步步高升）.
The condiments are finally added. First, peanut crumbs are dusted on the dish, symbolising a household filled with gold and silver. As an icon of longevity, peanuts also symbolise eternal youth.
Words: Jin yin man wu. （金玉满堂）
Sesame seeds quickly follow symbolising a flourishing business.
Words: Sheng yi xing long. （生意兴隆）
Deep-fried flour crisps in the shape of golden pillows are then added with wishes that literally translate to mean the whole floor would be filled with gold.
Words: Pian di huang jin. （遍地黄金）
All toss the salad an auspicious seven times with loud shouts of lo hei and other auspicious New Year wishes.
Words: Lo hei which is Cantonese for "tossing luck".
The ingredients are mixed by pushing them toward the centre, an encouragement to push on the good luck of all at the table.