You do different things against different players.You go and watch my match against Rafael Nadal at the 2007 Australian Open, and I was playing pretty close to the baseline in that match and taking a lot of risks because I think that's the right way to play against him.Against Federer I don't think that's the right way to play. I'm not going to play that sort of game against someone that defends as well as Federer does.My serve is clearly much better than it was two years ago. I feel quicker and stronger around the court. Mentally I feel like I'm better.But there are still some things in my game that I want to improve and it does take some time to put them into the match court. I feel like I've started to do that this year.