Check your transmitter for EPA/endpoint/travel adjustments (different terms for the same thing). And dual rate, make sure it's turned up. What transmitter do you have?

If nothing left there, or you don't have those features, consider a longer servo horn. Or a shorter lever position on the other end of the link to the servo. What RC do you have?

Be sure to not overdo it, you don't want to bind up the servo against the steering mechanism.