The Perl Debugger (perl -d) is your friend. The 'm' command reports on the various methods available to an object; use it just after you have instantiated the beast --
in reply to Understanding Chaos
'T' gives stack trace information and tells the context the routines are called in.
I also use 's' step into method calls and then explore with 'w' and friends to see where I really ended up.
my $obj = Class::new();
DB<1> m $obj
In terms of graphics, I have yet to find something that beats pencil and paper for the fine detail, white-board and Visio diagrams for the over-all structure.
And Document Everything! Build POD, ReadMeFirst files, Twiki pages, what ever make you comfortable. Even if you don't have to come this way again, someone else will.
I Go Back to Sleep, Now.