Managing your inventory and skill bar properly takes very little time and effort in Twelvesky2. How you do so is up to each individual, however there are many things that people do in common to save time. Generally, people use the first few columns so that they can quickly replace stacks on their skill bar as they become empty. Use your trade window to store valuables and throw away anything you do not.
The sale of public resources and unique offers little income, is a waste of valuable time. Keep it for your return scroll and retention of local stack in a corner, so that when you pick up the items(12sky2 Gold). On the right of your skill bar, keep 1 stack of chi pills and to the left of that, 4-6 stacks of hp pills. This is the most efficient setup and allows you to replace essential hp pills quickly. Place attack skills and the run skill on the left of your skill bar and buff skills in the middle.
Duplicate this setup and vary the skills on your alternate skill bars for Twelve Sky2 Gold PvP, PvE, and buffs. Then, by simply changing you skill bar, you can access any of your skills while keeping pills constantly at the ready. All of these minor things by themselves will not directly increase the rate at which you gain experience, but they will save you time and the less time that you waste, the more time you will be spending killing monsters and the more experience you will gain in the long run.