First Step 5
Win a fight in either Story mode or 1 Player Arcade mode.
This should be your first achievement. You will get this with natural progression of the story. You can obtain it in Arcade mode, but I suggest saving that mode until later. You will not get this in training mode, but in the first tournament.
New Champion 10
Win against the leader of the first Tournament.
After beating the last dragon in the first tournament you will gain this. This should be a very easy tournament.
Win the first Tournament without being defeated.
*CAN BE MISSED*
You should get this with no real issue on your first tournament, after beating the final dragon there. A defeat counts as your dragon being knocked out. Make sure you have trained your dragon completely first, and set the attribute points in the Den. If for some reason you lost, just load up the last save and try again, or worry about it in your second playthrough.
Young Competitor 5
Earn a gold medal in any challenge on Novice difficulty.
After you are done with your tournament and found all of the tools required to fix the bridge (by talking to various people in the town), you may cross it and do the challenges. Get one gold medal on any of them that are currently unlocked.
Ultimate Customization 15
Unlock all customizations of a dragon family.
After your first tournament, you should go back and train your dragon. Make sure to complete all trainings, then go complete the rest of the challenges aiming for gold medals. Upon your first gold medal this should unlock as you gain customizations from trainings and challenges.
In Great Shape 15
Win the second Tournament without taking care of your dragons during it.
*CAN BE MISSED*
At this point, you probably didn't even know you could do this. The option is yours to exit the tournament to heal your dragon but in reality you never need to do this if you had them at full health in the first place. Make sure and have a backup save file just in case you accidently exit the tournament before it's over.
Win against the leader of the second Tournament.
Story related, cannot be missed. The leader is the top character on the tournament chart. You must beat characters below him/her in order to gain the rights to face them.
Earn a gold medal in each challenge.
After completing the 2nd tournament, all of the challenges will be unlocked. Go ahead and finish the rest up and this will unlock after you have gotten a gold medal on all of them. *Only novice difficulty is unlocked for now*
Great Speaker 15
Talk to every person on the island in Story ode.
As you run around, speak to everyone you see. Very easy to find them all, except one which is not available until later after the second tournament when your dragons escape. They are now in the custody of a Viking in The Wild. He is hard to notice at first. Coming out of the challenge cave, go up the hill to your left. The camera angle hides it until you veer off onto it. If by this point you don’t have it, just go make sure you talk to everyone again.
Win a wild fight.
The wild fights become available after the second tournament and are located on the beach by the challenges. You will have to talk to the Viking and beat him. You must face him in order for your story to progess, as he is the one who has your dragons that had escaped. You must fight him with a new one you receive at the docks.
Rich Harvest 15
Gather 1,000 common ingredients
As you run around you’ll be picking up all kinds of common ingredients. You slaughter animals walking around, pick them from gardens, break open barrels, and even find them under rocks. You have to get them to feed your dragons to keep them healthy. You should get this through normal play. The challenges will be giving you a lot as well, so no need to go out of your way for this. The Dragon's Den is a great way to reset the items you gather. Just go inside and exit, and everything will appear again.
Have a dragon with 20 points in a characteristic in Story mode.
Go to the den and click on any dragon, then hit RB to move to “Characteristics”. Each dragon has one bar that goes 20 points. Fill up any of the bars on any of the dragons to the full 20.
You can subtract those points whenever you want to at any point in the game to redistribute them. You can get this very early in the game before the 2nd tournament.
Win the third Tournament always fighting the lowest rated opponent.
*CAN BE MISSED*
This achievement can be missed easily if you don't pay attention. In the third tournament, every opponent you face must be the lowest possible on the list (the exact one above you) as the ones you beat get greyed out. Sometimes it will be annoying and someone will show up again to face, but just keep at it. With an upgraded dragon, you should be able to beat every opponent without losing a single match. Keep an extra save file before this tournament just in case!
Win against the leader of the third Tournament.
This is given after you complete the third tournament. Remember to always beat the lowest rated opponent to gain the Valiant achievement as well.
Dragon Doctor 15
Have 4 dragons in a great shape in Story mode.
After the third tournament you can go get your final dragon at the docks. Afterwards, go to your den and get every dragon you own into blue health status. They don’t have to have 100% full bars in every category, just need to be in great shape (aka blue health bar). You may need to go gather ingredients if you are running low.
Weapon Master 15
Make a dragon finish all trainings.
Another achievement to get after the third tournament, you must finish every training in melee and fire with one of the dragons. You do not have to do any of the tutorials. I suggest completing all of the trainings for all of your dragons, since you have to have them at max level later anyways.