I have some deck building advice.
 
1.) No more than 3 proffessor oaks. That's drawing about 21 extra cards which is good because it usually gets you the cards you need to win but also gets you a little short on cards.
2.) No more than 2 stage 2 pokemon(of the same pokemon). Take blastoise for instance. If you had 4 blastoise's then you would have to have 4 wartortles and 4 squirtles. That would take up almost all of the room in your deck for pokemon.
3.) As many basics as you want (of the same pokemon). If you had 4 chanseys that would only be about 1/4 of the room for pokemon in your deck, then you could put many more pokemon in.
4.) Not more than one scoop up. Believe me, they rarely come into use.
5.) Use four energy removals, energy removals RULE. They could come in very handy, especially after a charizard uses fire spin.
6.) If you have some stage 2 pokemon in your deck, then put in pokemon breeders. Say for instance if you had an alakazam in your deck. Instead of putting in 2 kadabras you could have two pokemon breeders( that's just an example. If I had a psychic deck then I would have no alakazams and probably 3 kadabras).
7.) Use pokemon traders(duhhhhhhhh). I noticed that many of my freinds have no pokemon traders in their decks(maybe they don't have one or something). It's a very usefull card. It lets you get out those pokemon that you only have one of in your deck.
8.) Always, always, always, always have a chansey in your deck. It is the best wall and is great for  those suicide missions against your opponent's pokemon.
9.) Just like with chansey,always,always, always, always have dragonairs in your deck. Dragonair is basically an energy removal with 80 hp that can also do 20, 30, or even 60 damage.
10.) The same with farfetch'd. Farfetch'd is always a good pokemon. It can do 30 damage with 3 COLORLESS energy. It may seem like a lot of energy for only 30 damage but keep in mind that those 3 energy can be ANY energy.