In Singapore draft evasion is really punished hard.
What I can say is, if the law is implemented well, you will never truly escape from the evasion.
What can I suggest is try getting sick. Permanent injury is a sure way to escape, but I think you don't want to get that one. Some contagious disease can also make you exempt, but most of the time it is just delaying the inevitable. In Singapore if we are drafted the companies employing us must keep our position (they can't fire us, we keep our position and salary level after we finish our draft).
In reality, draft is not so bad. Even in countries where most of the guys are rich, like in Saudi Arabia, all of the boys must be drafted. Even more, being in military will teach you a lot of skills, and generally make you tougher in life. In Singapore we will be sent up to positions according to your physical score. If you are a tough guy, you will be sent up to special forces, paratrooper companies. If you are average, you will be sent up to marines or ground troops. If you have lower score (like I do) you will be sent up as drivers, logistical officers, couriers, or communication officers.
But in all classes, basic training (physical strength, use of infantry weapons and squad tactics) will still be taught.
So, my advice is just enjoy the draft.
The only thing I missed is just there are no girls you can meet for years.