Everybody's deck has a Weakness, especially mono-colour decks.  However,
there are certain cards you can add to make your deck get a comeback against
your Weakness.  Unfortunately, most cards of a type require energy that will
take up precious deck space.  However, every type has a couple of cards that
only attack for colourless.  I'll point these cards out.

Grass
Grass's generic Weakness is Fire.  Some grass Pokémon are weak to Psychic,
if you use them follow the tips under the Fighting/Psychic section.  There
is only 1 water Pokémon that uses colorless, and it's TR Squirtle.  For a
DCE, it can do 20-which is pure average.  50 HP, okay.  The rest is just
standard Water.  He's not much, but in a Grass deck he can protect against
fire.

Fire
If you run a fire deck, there are two tools to help you defend against
water.  The first is Base Voltorb.  Can work on colorless, but 40 HP and
Weakness to Fighting make him pretty weak.  The second(and better) is the
Lv. 10 Lt. Surge's Pikachu.  Quick Attack can use a DCE for an average 15
damage.  Plus, it has free retreat in case your opponent pulls up a Chan! 
Some water Pokémon have Weakness to Grass, but they're all fairly weak, so
you shouldn't worry.  If you insist, throw in a Scyther.

Water
Water is weak to Lightning and (sometimes), Grass.  In order to deal with
Electric Pokémon, there is no real tool-just run Articuno or Gyarados or
something like that.  If you want to run Gyarados or some other grass-weak
Pokémon, also put in some Blaine's Ponyta Lv. 13, or some other Fire guy who
can defend against Grass.

Lightning
Lightning is usually weak to Fighting.  However, if you have Zapdos/Rocket's
Zapdos, it has Resistance to Fighting, so you might want to put that or any
other flying Pokémon in there.  Rocket's Zapdos is the best to keep your
other Lightnings safe, though.

Fighting/Psychic
Fighting and Psychic are grouped together due to they're both genericly weak
to Psychic.  You can use the Ghosts(Gastlys, Haunters and Gengars, as well
as Misdreaveuses when the Neos are here.)  But, if you use Fighting and
don't wanna put Psy in your deck, you best bet is most colourless
Pokémon(Rattata/Raticate is a must-have if you're worried about Mime.)

Well, that's the conclusion of the first of Wartoise's Cool Comments. What
do you think?   E-mail me at the address below.

Wartoise@hotmail.com