How to Grind for levels(Need advice)

shibatatim

I've been playing CoTK for awhile now and have reached level 82. However, I have seem to hit a wall with the millions of experience points to advanced to the following levels. Lack of rewarding experience for later Instances doesn't help, but World War seems to be the best bet; Trial Tower has been reduced to just 'sweeping' through the turns. Recently I have purchased Chief Exp +30% with Gold and seems to help in World War.

Tonight I'll more than likely reach level 83; defeat Xiahou Dun, recruit him and pass a few more Instances. However, from my experience so far and lack of a better way to proceed, it shall take at least a week if not more to reach another level. Which leaves me kinda stuck grinding and really not reaching these millions at a satisfying rate. If any of you have some advance please reply here. Thank you for your time.