Just follow the equiment guidelines that we 've set up, and you'll be fine.
If you find items in the Mud that break those guidelines, just typoreport them and we'll fix them.
Note that the fact that there may be some bad items in the game, doesn't mean that the guidelines are invalid.
If you for some reason want to make an item with higher stats, discuss it with a Head Builder first, and make sure that the quest needed to get the item is hard enough to motivate the high stats. (This too is actually stated in the guidelines).