There are many excellent garages in the Tuning Forum and lots of tunes you can try. There's a lot to know about tuning and what works and what doesn't. You can start from scratch and learn as you go, or go to the Tuning Forum and try out some of the tunes listed there. Just make sure the tune was made online for online racing and for the type of tires you intend to race with. Taking an offline tune online, won't likely work and taking a Sport Soft tune and putting Racing Softs on the car won't work very well either.
Good luck.