A simple architecture or a simple algorithm goes a long way toward achieving high maintainability. Remember KISS. Also, as you decompose software into subcomponents, remember that people have difficulty comprehending more than seven (plus or minus two) things at once. C.A.R. Hoare has said:
There are two ways of constructing a software design. One way is to make it so simple that there are obviously no deficiencies and the other is to make it so complicated that there are no obvious deficiencies.
