Yanmega Prime Cobalion - Bol1c

3-4 yanmega prime
1 virizion
2 bouffalant 
2 druddigon
1 tyrogue
1 cobalion
3-3 zoroark
1 zekrom
1 durant
Pokemon = 22


1 rocky helmet 
2 pkm catcher
3 junk arm 
3 pkm communication
3 judge
3 collector
1 cheren
3 oak theory
1 switch
3 copy cat
T/S/S = 23


4 double colorless
3 metal 
2 special metal
2 special dark
3 grass
Energy Total = 14


Strategy
Virizion is the ideal starter with its draw attack (and it's also a decent attacker).  Yanmega prime is a great attacker because of the free cost, as long as you have the same number of cards in hand as your opponent.  Yanmega is weak to lightning, the biggest deck in the format, so there's zoroark and coballion to counter it.  There's lots of other pokemon in the deck, but they don't work as well together as the ones that I've mentioned.


Pokemon Analysis
Since virizion is the best starter for this deck, I'd increase it to 3.  You should be fine with a 2-2 line of zoroark.  Coballion is important in those electric match-ups to prevent your opponent from attacking, so I'd increase it to 3 as well.  Everything else I'd drop.  Shaymin EX would be a great card to add in since you're already running grass energy.  It would only be used as a late game attacker, but if your opponent had only 1 prize left, using N and attacking with shaymin would make it more difficult to return the KO.


Energy Analysis
Since yanmega doesn't need energy, we'll focus on more of the metal. 2 DCE, 4 special metal, 4 prism and 4 grass should give you a nice combination of energies to work with your different types.


T/S/S Analysis
I would drop the rocky helmet and add eviolite instead.  With the special metal on coballion, that should make it even more difficult to KO.  A 4th junk arm would be ideal to re-use trainers.  Other than that, I don't really have any other suggestions.  If you can fidn the room, I'd consider adding a couple of N for late game disruption to help you catch up on prizes (if you're behind).  It's a great combination with Shaymin EX as I discussed earlier.


Overall
This is a very interesting deck, but one that will likely struggle at tournaments since it doesn't have any energy acceleration to be able to keep up with the faster decks. You'll have to be very careful about your energy attachments and possibly look at shaymin as a possibility to conserve energy.