I’ve tried several different methods for character sketching — keeping track of their relative ages and kinships -- and my current favorite is a Synium product, known as MacFamilyTree 7 for my laptop and as MobileFamilyTree 7 for my iPad and iPhone.
It is easy to use and generates several useful views and reports. One of the most useful is an interactive chart that shows relationships but that also lets me click on any of these people to edit or add relatives.
The Timeline View lets me see the relative ages of the cast of characters.
The Person Report lets me keep track of individual characteristics and events as well as kinships to other characters.
Because it can be stored in the cloud, I can be typing away on my laptop and use the iPhone or iPad to keep an eye on characters.