When drawing or painting, try to work from the top corner opposite your dominate hand to the lower corner of your dominant hand.  I’m right handed so I SHOULD start my drawings from the upper left and work across and top to bottom right.  Also, you could use a piece of paper or a dowel rod to rest your hand on if you need to work an area that has already been worked on.  This would keep me from smudging my drawings as often as I do, and possibly keep me from dragging paint everywhere.    I won’t go into how this came up this week, just trust me.  How’s that Beatle’s song go? IIIIIIIIIIIII should’ve known better….