You have to visit your house after work instead of going to the gym, library, arcade, or the construction area. So you have to give up the opprotunity to raise your stats that day in order to save.
Or crack the save file. Here's my notes on it. I only know what a few fields do, and only have speculations regarding the others, but this covers the really important ones. (The [ and ] specifies arrays. You'll see what I mean if you edit the file.)
Save file format, Shift-JIS
[
"name",
day,
[akirascore, integer?, integer?, karinscore, makotoscore],
[money, strength, intelligence, beauty, stress],
[scenesarray?],
[scenesarray?],
boolean?,
integer?/void?,
integer?,
[date1boolean, date2boolean, date3boolean, date4boolean],
boolean?,
boolean?,
[makotosworkoutscene, alphinascene, narshascene],
boolean?,
]