Measuring a Unit's Arc of Sight

Units have a 90° arc of sight to the front. The quickest way to measure this arc is by projecting a 45° angle from each side by diagonally bisecting a square using a straight edge, such as the spine of a book or a measuring stick. The square is formed by one or several bases in the unit. Cavalry bases are 25 x 50 mm and so a square can be formed by considering two adjacent bases.

Proxying Artillery and Scatter Dice

It's easy to proxy the two special Warhammer dice using a D6:
To proxy an artillery die, roll a D6 and double the result, '6' is a misfire.
To proxy a scatter die, roll a D6 and use the position of the '1' (round the edge) as the direction of scatter, '1' and '6' are direct hits.

Shooting

Here's a quick and systematic way of working out what you need to roll to hit when shooting:

Remember that a roll of 1 always fails to hit.

For example, if an Empire archer (BS 3) moves and shoots (-1 modifier) at long range (-1 modifier), then

so he needs to roll a 6+ to hit.

Armour Saves

Here's a quick and systematic way of working out what you need to roll for armour saves:

If S ≤ 3 or if the weapon has a special save modifier, then set (S - 3) to 0. Remember that a roll of 1 always fails to save.

For example, if a Chaos warrior (4+ armour) is wounded by a Dwarf handgun (Strength 4 and Armour Piercing), then

so he needs to roll a 6+ to save.