You don't spend much time on breeding and EV training.
- Your Dragon team is totaly cool, but you should look more carefully for natures and IV's. For example: Your Garchomp's nature is Calm, (+Sp. Def, - Attack), which is very "bad", because Garchomp's base attack stats is 130 and it's Sp. Def stats is only 85. You should think about training in it's attack stats (but you necessarily need a Garchomp with a different nature, I suggest Adamant or Jolly) And also Garchomp is quite fast (base 102), so training in speed stats, wouldn't be a bad idea. And it's also important, that your Garchomp uses Physical type attacks (attack stats), because it's Sp. Atk. stats is very low and using Special type attacks won't deal any searious damage to your opponent. Only this way your Garchomp can unleash it's real power in a match.
What I suggest is, to find yourself a Natures, IV's and EV's guide. Those are only the basics for maximize your Pokemon's abilities and it's true power.
It's also important to make your own tactics for your team (weakness > advantage).
What I'm saying is not, that your team is bad, or that you're a bad trainer... I just want to help you to be even better, then you're now. :15: