Well, if you can't see the small parts, work from top down first. I've often coded things as:

my $data = get_data();
process_data($data);
print_result();
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literally, as if it were pseudo code. Then I write stub routines, like:

sub get_data {
  # returns scalar data pointer to my structure
  my $return_value;
  my $db = open_database($credentials); # must declare this above
  my $data = query_db($db, "select * from bar");
  $return_value = massage_data($data);
  return $return_value;
}

sub open_database {
  my $cred = shift;
  warn "open_database doing nothing";
  return undef;
}
...
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and so on... Then at any time, I can "run" what I've got. And stay focussed on each area of development. If I need a class, I'll develop a generic class that I can plug in.

Again, the goal is to type a dozen-ish lines of code, then invoke it. That's nearly always been possible.

-- Randal L. Schwartz, Perl hacker