#define _can_fire skill99 //will write my.skill99 when compiling but makes it easier to read

#define key_fire key_a //same as above for for pressing key_a... change to appropriate fire key
while(key_fire){

   if(my._can_fire){
     my._can_fire = FALSE;
     //bullet_spawn / call fire script, ent_create(bullet etc,,,
     wait(-1); //wait 1 second until can fire again
     my._can_fire = TRUE;
   }
}