How to increase splendor+ mileage?

i'm in chennai. i bought a splendor plus in november 2009. at first it gave a mileage of 40 kmpl. i was driving it rashly from beginning. after the first service, it gave me 50 kmpl. i adjusted the carburetor for good mileage in the service center. still it gave me 50 kmpl only. so i went for a private mechanic for second service. but now too it gives me only 52 kmpl. he also adjusted my bike for best mileage. what everyone tell is, as i have drived my bike rashly in earlier stages itself, it will not give good mileage at all. and my bike's full throttle also goes upto 80 only. it never crossed aboe 80 km/hr speed. but one of my friend using the same splendor plus tels he is getting mileage of above 65 and top speed races to 95. i need to improve my bike's fuel effeciency and also i should attain full throttle speed atleast upto 90. pls give me any suggestion. my friends asked me to remove my bike mirrors and saree guard so that it increases both effeciency and top speed. i couldnt find what actually my bike's problem is. pls answer me bike experts...........