Not sure if Growth Fetishes apply to Age Progression, but I was wondering how to make good, fluid, logical age progression pics(i.e. just draw them as older).  I don't wanna make the pic look random and inconsistent.

And if it's a female...which it may be most of the time, I don't wanna unwittingly make the breasts like super huge when they're older...

So any help is appreciated.

One method that works for many of us --
Draw the "after" and "before" sketches first and then draw a series of interpolation sketches based on how many steps or stages the age/growth progression will take. 
So, for example, if you are planning on five stages -- draw stages 5 and 1 first and then draw stage 3 such that the characteistics are half-way between 1 and 5.  Then draw stage 2 such that the characteristics are half-way between stages 1 and 3.  And, finally stage 4 with characteristics that are half-way between stages 3 and 5.

Tschuss!
Hunter