One of my "hobby resolutions" for 2017 was to increase the precision in my play. I don't mean become more cold-hearted rather make sure my movement and placement of units is more exact leaving little room for surprises.
The first step along this journey was to use my opponent's turn to plan my next move - rather than determine whether the cat needs to go to the vet, what am I going to cook for tea etc. Yes, circumstances might change but you should at least have an idea of what units are going to do what next turn. By doing this you free up time to concentrate on the actual placement of your units.
When it comes to moving your units, you should know the order in which they have to move so that you can achieve your plan without impeding yourself. Hopefully, your previous turn has kaftan the necessary lines of sight for charging units whereby you suddenly discover you can't do that combined charge.
I am increasingly using markers to determine the starting position of my unit so that I can re-place the unit if a particular move does not work out in practice. By marking where it starts you get away from the "I think it was here" conundrum..
Two of the most important tools you can have are an Arc of Sight (Ironheart Artisans) do a good one and a Laser Pointer (Army Painter). The first is essential, the second while not a must have is a worthwhile tool. These allow you to check your facing and ensure you are not inadvertently leaving a flank open to the enemy. One thing I check on a charge is where I will be if I bounce.
Another various useful habit to get into is your gaps between units. If you place another unit or character too close it will restrict your options in terms of pivots. Recently I posted about the 50mm rule and I am now well aware of what units can turn 90 degrees and move given a 1" gap and which need 2" or more.
Finally the best advice I can give is talk to your opponent. Tell him what your intentions are with a particular move e.g. "I am facing this unit, outside your charge range. I have checked my flank arc and your cavalry are in my front. Do you agree?" This removes so much potential for later confusion and for disagreement.
Kings of War is very much a game of distances and angles. However you have the ability to pre-measure everything so with some planning you can make your movement/placement more precise and that will undoubtedly improve your outcomes.