Well driving style is a mix of technique and strategy.
For the technique I tend to use my own custom setups and not the ones found on SetupGrid or Inferno. This is because they might be awesome for hotlaps, but are quite limited for racing actions (passing, cornering side by side, etc..). Indeed, they are made to follow the line, and each disturbance results in an incredibly huge loss of speed compared to a setup built for digging your way to the up of the pack.
As others, I like setups that are "slidy" (understeering wheels-tires setups-suspensions but with oversteer at the entrance), and I prefer to rely on my footwork than my hands.
About the tactic, since I moslty race the XRG (god I love this car) against other XRG and XFGs, i tend to use the power of my car at the start to gain 3-5 places. Then, if I lose some during the race, it is okay. For passing, I tend to be very mean, given that I build my moves during about 3-4 corners (creating pressure on the guy, to make him fail epically), or I just seize an opportunity of there is one and rush into the inside at the beginning of the corner, to block the dude.