Substitutions: Teams are allowed to use rolling substitutions, with no stoppages in play per substitution and with unlimited substitutions per quarter. Standard international rules only allow substitutions either between quarters or when a player is injured.
Two-point shots: Similar to three-point field goals in basketball, the goal shooter (GS) and goal attack (GA) may shoot goals from outside the shooting circle. These goals count for two points; in a power-play quarter, they would count for four points. Umpires raise one arm for a single-point goal and two arms for a two-point goal. In standard netball rules, goals can only be shot from within the shooting circle and count for one point only.
Centre passes: After each goal, the team that conceded the goal takes the next centre pass; teams alternate taking the first centre pass of each quarter. Under normal rules, a coin toss determines the first centre pass of the match, after which centre passes alternate between the two teams.
Timing: Each quarter lasts only six minutes, compared with 15 minutes in normal international netball competition. Breaks in between quarters are two minutes each. Injury time-outs are 30 seconds only; standard rules allow for one initial two-minute injury time-out.
Power plays: Each team can separately nominate one "power play" quarter, in which each goal scored by that team counts for double points.
Note that some parts in the Wikipedia article are not accurate. Coaching is allowed from the bench at all time in both regular netball and Fast Net. Also, I have understood that at the end of a Fast Net game, when it's a tie and a winner needs to be declared, play continues until one team leads by two goals.