How hard will it be to lose 5-10 lbs?

Im currently 6ft 11in and weigh in at 183-188(I think lol) and Im aiming at 170 lbs since thats what my doctor said my body m something index said someone my height should be, but Im hearing 170 at my height is bony and chicks are NOT digging that so Im stuck. Personally I feel that my arms are looking better but ,my target for those 10 lbs is my abs. How hard or what type of excersise would I have to do to lose or tone that in a month? Ive been doing some Aerobic/weight training with my Martial arts school so thats been good but what should I be doing to "Target" my abs.