When either serving side or receiving side commits a fault, a point is awarded to the opponent side including making next service.
The winning point for a set is 21 points, unless the point is tied at 20–20, the set shall be decided on a difference of two points, up to a ceiling of 25 points. When the score is tied at 20–20, the referee announces “Setting up to 25 points”.
The game is played in 2 sets with 2-minute rest in between.
If each "Regu" wins one set, the game shall be decided in the third set called "Tiebreak" with 15 points unless the point is tied at 14-14, then the set shall be decided on a difference of two points, up to a ceiling of 17 points. When the score is tied at 14-14, the referee announces “Setting up to 17 points”.
Before the tiebreak set takes place, the referee shall toss a disc or coin, and the side winning the toss shall have the option of “Choosing Service”. The change of sides takes place when one “Regu” reaches 8 points.
Adapted from: http://en.wikipedia.org/wiki/Sepak_takraw#Scoring_system