In regards to units that don't want to stay in line, both ground and space, my tactic is this: Select a unit, select it's target, immediately hit the "S" key. This orders the unit to stop, and prevents them from breaking formation, while still firing at the target you selected for it. Can be used in combination of Control+Left Click (to select all of that type on screen). Also, you can hold right click, and very slightly move the mouse in the direction you wish a unit to face, a green arrow will appear showing the direction. Great for when the enemy attempts to end run around your ISDs. Select the unit, right click where it already is, move the mouse slightly to the direction you wish it to face till the arrow appears, release right click. The unit will rotate, albeit at a slower pace. But better than it going off blindly in a random direction.