In my sheet, I've got, basically:
Header: Name, gen, supermax skill, max career, Building, Property (with tick boxes for upgrade levels).
List of Opportunities done, tick boxes for "is this a Black Op"
List of Lifetime Rewards bought, tick boxes for "Is this one of my unique rewards"
List of Unique Best Friends (which I fill out at the end), since it can change rapidly
Tick boxes for Portrait, Sculpture, Photo at each life stage.
I found it easier to make hard-copy printouts of the basic sheet and keep track with pen and paper, but that's partially due to a peculiarity of my system - if I alt-tab away from Sims, then when I switch back, the graphics are very dark. This also gives me the opportunity to make notes on the back if necessary.
To some extent you need to do what works for you as far as record-keeping - my system may not be to your taste.