To bring your dragon into battle you need to be Level 5 or higher.
Keep in mind that your kingdom's power level also contributes to your dragon's strength.
Always keep an eye on your mailbox whenever you send troops into battle. You'll receive a battle report once combat is over with information about your victory or defeat.
Joining an Alliance gives you the chance to coordinate attacks against enemies, to share strategies together in Alliance chat.
You can only research magic up to the same level as your Wizard's tower. So update the tower first then the rest.
The more troops you have, the greater your assaults will be too.
You can get free Crowns by watching promotional videos.