Argentina striker Aguero has not featured in any of City's pre-season friendlies after helping his country to the World Cup final.
The 26-year-old also suffered injury in Brazil, with fitness issues also limiting him to just 23 Premier League appearances last season, though he still managed an impressive 17 goals.
City's faith in Aguero was displayed in the striker penning a five-year deal on Thursday and keeping him fit will be crucial to manager Manuel Pellegrini's hopes of retaining the Premier League title.
Speaking at the club's CityLive event on Thursday, Aguero detailed the extent of his regime as he looks to lead City to another top-flight title this term.
"I got back here last week and the aim to begin with is two weeks of just hard work to strengthen the legs and to get my fitness right," he said.
"Right now I need that because it's been a good while since I did even a mini pre-season of at least a fortnight.
"By the third week I'll be fully 100 per cent and ready to go.
"I have to get in an hour and a half early and start off with strength exercises and then I work on stability in my hips and sides and then the rest is more straightforward, just to strengthen the pelvic area in order to prevent any further injuries by the groin area of the sort that I'd been having."
City were too strong for any of their title rivals last term, holding off a valiant effort from Liverpool as Chelsea and Arsenal faded from contention late in the season.
Manchester United, however, were never in the race and ended up finishing a lowly seventh in a disastrous season under David Moyes.
But Aguero believes United will come back strong under Louis van Gaal and expects City's near neighbours to be their main title rivals.
"This year I think Manchester United will be up there challenging us," he explained.
"Then you have teams like Chelsea and Arsenal who, as always, will be there or thereabouts battling with us for the league.
"But the team I think who is most worthy of having the best chance to threaten is United, because they are not involved in any other competitions other than the English knock-out cups and the league.
"That means they'll get more rest between games than ourselves and some of the other teams and that will work in their favour, like it did last season with Liverpool."
