>This deck was changed around when Fossil came around.
>It focuses on getting either Magneton out (I think they are equally good)
>or Weezing and using Selfdestruct. Electrode is there to help out with energy
>costs and Nidoran(F) and Nidorina are there for backup. I know there is 
>something
>wrong in here because of a recent losing streak. Please help
>me!
>
>3 Magnemite
>1 Base and 1 Fossil Magneton
>3 Voltorb
>2 Base Electrode
>3 Koffing
>2 Weezing
>3 Nidoran(F)
>2 Nidorina
>4 Double Colorless Energy
>10 Grass Energy
>12 Electric Energy
>3 Potion
>3 Gust of Wind
>4 Bill
>4 Super Energy Removal
You've got a good, solid theme here. But some of the cards that I overwhelmingly see present in these decks is lacking within your structure. We'll look into adding those in, but first, let's take a look at your pokemon. Magnemite is probably the most famous of the destructors, for two energy being able to do 40 damage is quite nice. But Voltorb and Electrode aren't going to really help this deck a lot. Neither is the Nidoran line. So let's scratch those two and look at the weaknesses of our pokemon. Magnemite/Magneton is weak to Fighting... since we're playing Grass, let's use Scyther to counter that Fighting problem! Koffing/Weezing is weak to Psychic. Some of the best pokemon that are Psychic resistant out there are colorless! Great, this should be easy for us to cover our weaknesses on.

Pokemon (15 Basic + 6 Evols = 21 Total):
4 Magnemite
3 Magneton (2 Fossil + 1 Base)
4 Koffing
3 Weezing
4 Scyther
3 Chansey We've got a nice even deck on energy requirements here... so we'll go with just slightly more Grass...

Energy (20 Basic + 4 DCE = 24 Total):
11 Grass
9 Lightning
4 Double Colorless Energy

Finally, we need trainers. We've got room for (60 - 21 - 24 = 15) 15 trainers. Beyond our normal card drawing, we want to choose trainers that support our theme. With Self-Destruct techniques, one of the best trainers is Defender!

Trainers (15 Total):
4 Bill
2 Professor Oak
1 Gambler
1 Computer Search
4 Defender
3 Gust of Wind

Good luck as you venture forth to blow all those pokemon away!