The short answer is "you aint gonna be able to do it... not in the real estate market... and tough otherwise as well".
Residential real estate is swamped with agents. Loans are tightly restricted with 20 percent down being the norm. Breaking into this field will be tough... and probably not very lucrative.
Commercial real estate: The government SWF Temasek is a large investor in big projects and a handful of real estate tycoons really control the market. I don't know enough about this area but suggest that this is a rather exclusive club that doesn't let you in just because you ring the door bell.
Unless you are some kind of accomplished deal maker I don't know why a company would hire you given the level of expertise here and I don't know why the government would give you an employment pass when locals can do the job. Hard facts... especially right now in the down turn.
As for business, the rules for the Entrepass, your right to start a business in Singapore, are about to be seriously tightened up.
http://www.mom.gov.sg/publish/momportal ... epass.html
The long and short of it is this: The government is under lots of pressure to 'stop letting foreigners have all the jobs' even though the low wage jobs still don't get filled and even though Singapore wants to avoid the depression like conditions in Dubai caused by the repatriation of so many expats all at once.
Then, there are the expats here who have lost their jobs and have nothing to go home to. They are applying for personal employment passes and PR in droves to try and stay here in the hopes that a job will turn up.
If you have an idea for a business and the capital to finance it, then this might be the best route. Getting started could be tough as this is a fairly tightly networked community... if you are trying B2B you'll be a complete unknown, B2C... might work but there are millions of folks out there in this game.
Good luck.