If you are taking over the maintainership of DBD::ODBC - good luck.  I
don't want to say anything more that will put you off ;-) so honestly,
good luck.

However there are a few things I can say that might help you:

o make sure you install Test::Pod, Test::Pod::Coverage and
  Test::Kwalitee as tests using those modules only get run when they
  are installed. If you don't install them you can bet someone else
  will (probably someone packaging Perl modules for a Linux distro)
  and you will have missed the failures.

o when a new DBI is released get hold of it, get the latest dbivport.h
  and copy it into DBD::ODBC.

o when a new Devel::PPPort is released get hold of it and copy the
  latest ppport.h into DBD::ODBC as dbipport.h then persuade someone
  looking after DBI to change DBIXS.h from

  #include "dbipport.h"

  to

  #include <dbipport.h>

  I never managed to get that done.

o remember that when a user installs a new DBI he generally needs to
  recompile his DBDs - people will forget this and it can cause a load
  of problems.

o a lot of people have worked on DBD::ODBC over the years and in all
  cases I know they were volunteers. This means it was not their day
  job and they did their best but sometimes took shortcuts. That
  sometimes means a patch was provided and it looked ok and seemed to
  solve a problem so it was committed and all was well even if the
  patch did not look so good.

o there are a lot of people using old and buggy ODBC drivers (or ODBC
  driver managers) and DBD::ODBC has a lot of workarounds for
  them. I'd suggest that if you don't know something is definitely
  broken then don't change it. I wasted some time trying to trim
  things down only to find I broke older drivers and driver managers.

o dbi-dev mailing list is your friend - use it.

o Microsoft wrote the ODBC spec then handed it to X/Open but continue
  to change it without reference to X/Open. This will happen again.
  Be aware of it and live with it (it has just happended again with
  ODBC 3.8!) and it hit me hard when 32bit moved to 64bit and the spec
  changed over night.

o at this time, unicode in ODBC NEEDS a unicode aware ODBC Driver
  i.e., it must have the wide SQLxxxW functions. People will tell you
  that the driver manager can "translate" between ANSI and WIDE APIs
  (or the driver can do UTF-8 etc) but it is nonesense e.g., unixODBC
  does an ok job of this but it does not work with bound columns, ODBC
  does not do UTF-8!