G'day all! Let's see what we have to work with.
>>>>
Hello satoshi!  Can u help me with my deck.
 
4 houndour (3 fire 1 dark)
3 houndoom
3 MP Mewtwo
3 Magmar
1 Magby
2 Cleffa
total 16
 
4 dark
2 rainbow
6 psychic
7 fire
total 19
 
4 oak
4 itemfinder
4 cpu
3 gold berry
2 GOW
3 eco
2 lass
3 energy flow
total 25
 
Strategy = Start off with magmar or mewtwo.  Then build up houndoom and crunch
flamethrower, crunch flamthrower.  Magby is there to kill plume and king.
Cleffa is there for the lass combo and for a new hand. Mewtwo is there for
the absorb and energy flow combo to get dark back.   The deck doesn't need
plus powers because of crunch.
>>>>

 

Wow. I play a deck just like this one. Spooky. =/
 
The Pokémon look good for the most part-let's just fix a few minor things.
Make sure all of the Houndour are the fire version-that extra 10 hp will
make a difference, trust me. Let's also remove the Movie Promo Mewtwo for a
fourth Houndoom, a Trash Exchange, and a fossil Gastly. Gastly, imo, is
better at getting back special energy cards-even if he does take 10 damage.
Plus, we don't need to worry about Mewtwo taking insane amounts of pain so
we can reuse those Dark Energy. Let's move on.
 
Remove the three Energy Flow for three Energy Removal. With the Gastly here
now instead of Mewtwo, we won't need them anymore. Finally, take out a
Psychic Energy for a third Lass. Three of that card works best, trust me.
 
Well, that about does it. Hope I was of some help, and good luck and happy
gaming!

~ Satoshi