Thanks for your mail!

Let's see what advice I can offer to help your deck do even better.
Here's the deck you submitted:

Pokemon (17 Basic + 10 Evolutions = 27 Total):
2 Ratatta
1 Raticate
2 Pidgey
1 Pidgeotto
2 Dratini
1 Evil Dragonair
1 Dragonite (Movie Promo)
1 Doduo
1 Dodrio
2 Spearow
1 Fearow
2 Koffing
1 Weezing
2 Exeggcute
1 Exeggcutor
1 Pinsir
1 Ekans
1 Arbok
2 Caterpie
1 Metapod

Energy (25 Basic + 1 DCE = 26 Total):
9 Grass
3 Psychic
1 Double Colorless
6 Fire
5 Fighting
2 Lightning

Trainers (6 Total):
2 Bill
1 Recycle
1 Pokeball
1 Energy Search
1 Gambler

Alright!  Let's see what can be done.  The first thing you need to fix is the fact you only have 59 cards in the list that you gave me.  All decks in Pokemon need to be exactly 60 cards.  So, at the very least, you will need to add another card to this deck.  I recommend another trainer as you are very low on these, and actually high on the others.

With any good deck that you plan on winning with, you need to start with your pokemon.  Just like Ash has learned in the show that it is the pokemon and how you use them that let's you win battles, so it is also true with the card game.  To build a good deck, the best way is to choose 3 or 4 of your favorite pokemon and fill your deck with them, then mix your energy and trainers to work with them!  Although my suggestions aren't the only way you could go, here is some possibilities that would require the least amount of changing to your deck.  On the left, I listed a mix that would be adding commons/uncommons.  On the right, I listed how you could remix if you owned more rares or wanted to trade to get them to make your deck even stronger.

Pokemon:                          Pokemon:
(15 Basic + 9 Evols = 24 Total)   (15 Basic + 11 Evols = 26 Total):
2 Ratatta                         3 Doduo
1 Raticate                        2 Dodrio
2 Dratini                         4 Dratini
1 Dragonair                       3 Dragonair
2 Doduo                           4 Pinsir
1 Dodrio                          4 Koffing
1 Pinsir                          3 Weezing
4 Koffing                         4 Ekans
3 Weezing                         3 Arbok
4 Ekans
3 Arbok

Now we need to get energy to work with these pokemon.  It is very important not to waste energy and trade with your friends or purchase a starter deck to get the energy you need.  For grass, purchasing an Overgrowth or Brushfire would give you plenty of grass energy for this deck.  If you can't get the Double-Colorless Energies, just substitute Grass Energy.  I usually recommend 20/4... so:

Energy (20 basic + 4 Double-Colorless = 24 Total):
20 Grass
4 Double-Colorless Energy

So now we need trainers.  The best method for determining this is to find out how many we can add first.  For your deck, we've got (60 - 24 - 24 = 12 left in the left column) and (60 - 26 - 24 = 10 left in the right column).  In almost every deck, I recommend 4 Bills.  They are easy to get and _extremely_ beneficial.  Drawing the cards you need to win is very important.  Seeing how we've got kind of a Poison theme going, we'll add cards to help with it.

Trainers (12 Total):              Trainers (10 Total):
4 Bill                            4 Bill
1 Professor Oak                   1 Professor Oak
1 Gambler                         1 Gambler
2 Gust of Wind                    2 Gust of Wind
2 Potion                          2 Energy Retrieval
2 Super Potion

Good luck!  Hope this helps you out.