1. Aiming for the feet (when possible) can help (most of the idle animation movement is in the upper body), or you can zoom in or switch to the overhead tactical view.
For skills/spells you can use the turn order portraits at the top of the screen to target.
For normal attacks, right click an opponent and select Attack (no effect if you miss click) or hold the Shift button down to queue commands and left click: if you get a red target selection indicator, release the Shift button, otherwise if you get the white move indicator, right click to cancel while still holding Shift.
Mod:
Stand Still When I Attack2. In the Game section of the options, near the bottom, uncheck 'Dynamic camera'.
3. Set the AI personality of the Source Hunters to None or Loyal, or leave one character far enough away they are not involved in the conversation. After character creation, that can be changed in the Inner Chamber in the homestead (opened after the Hall of Heroes).