In reply to wert:
Be humble. Be prepared to start all over again. (If you go on to trad, you'll have to start all over again - again!)
Drop down to a grade where you can onsight 100% of the time. Let's say it's F6a. Do twenty. If OK, do 20 F6a+. If OK, well... you can see where I'm going with this.
You'll get better at route reading. But you'll also get better at resting. ('Cos I hope you're resting when you're route reading.) You'll get better at breathing and relaxing. If you ever climb trad, all of these will stand you in good stead.
Grades are a benchmark. If you concentrate on skills (resting, breathing, relaxing, route reading), your ability to onsight will naturally improve. In it's own time.
Mick