Some random tips about mesh design...

Make sure all of your elements have the same Xi orientations. This is especially something to keep under close consideration if you are building a mesh by pointing and clicking in cmgui.

Make sure the elements are right handed  You want the cross product of the Xi1 and Xi2 directions to point in the +Xi3 direction.

For mechanics try to make the the aspect ratios of adjacent elements as similar as possible.

If you can avoid using hanging nodes or versions then do so.