Fortifying requires a huge amount of luck. To Fortify you must have a Weapon in which you would like to Fortify and Energy Stones. The stone level Varies from lvl 1-5. Each stone gives higher boost counting on the level. To Have a higher chance of successing foritfication. Usin ga lvl 5 Energy Stone will boost your chance of success. To get these stones you must either buy coins and buy these stones from other players. Farm these from Difficult and Heroic boats OR Colelct medals and going to shop>>>Barter>>>Medals and Looking for Energy Stone lvl 4 and 5. If your weapon is 5 strength or more. I suggest you use Divine amulet to prevent from downgrading your equipment. Using a 15% or 25% amulet also increases the chance of fortification. Good luck
There are some theories that can work or may notw ork but i will list ehtm
Never try to fortify after someone has Successed fortification for i heard it lowers your chance.
Failing Metallgury Before Fortifying can help you increase your chances
Failing a couple Energy stones as play b4 going to your real equipment can help.