Participating in the arena can result in a large increase in fame. Try using higher level characters with rare crafted items for a better chance of success. Note that one character will be locked into the arena battles at a time.
Crafting
Items can only hold a limited number of elements and effects. If the item being used as crafting material has a third element, the final item will have a random between those two elements. This may overwrite a beneficial element on the base item. Rarer items will give bigger crafting bonuses when used as materials. You can also craft the items that characters currently have equipped while they are battling.
Gems
Find the presents that are randomly placed on the map to have a chance at collecting gems. They will respawn a few minutes after being collected.
Leveling
Once a character has enough experience points, they will level up and can improve attack, magic or defense.
Titans
Fighting Titans are only worth it if you are trying to get the rare items rewards for being one of the top players. The fame that is awarded is smaller than fighting an enemy for a certain amount of time.