Do the dailies for Elite Instances. It gives you 4 every time. So far, that's the only way.

You can obtain shards for you character from daily missions and do 3 or 4 elite instances and from recruit seal treasure or tendo,etc.

I shouild've clarified that the only guaranteed way to get the fragments is by doing the Elite Instance daily. The others are purely by chance.

Yes, the plot instances and seal treasure are the only way. Actually, sweeping plot instances is quite helpful because although you don't clear any new instances, you still get items for upgrading your character (upgrading equipment) while completing the daily mission.

survival breakthrough reward c*so include this, thou like sealed, it's rather unreliable.