I have a 06 scion tc and i want to modd it but i dont know where to start? any ideas?

Its your car. Maybe add some LEDs under the car and under the dash. Also maybe paint the waterfall( near the radio) and the door( the silver part), and maybe paint the door handles. Also, you might want to get a theme. Like for an example black and Orange. Just so you know which direction you are going to go. Just do whatever you want its your car. :)