Here are several rules form last game.
Dividing to Conquer 40k6 pg 5
On occasion, you'll be called upon to divide the result of the dice roll, a characteristic or some other valve. Where this happens, any fractions should always be rounded up.
Context: Canoptek spyders were assaulting Hovering Vendettas. Decided to use Smash. With the extra dice from charging I would roll two dice for each spyder. Opponent wondered if it would be one die because Smash halves the number of dice rolled in close combat. Informed him when a characteristic is halved you round up. He wanted to make sure. Looked it. Thinking about this one further sypder Attack characteristic is 2. Smash rounds it down to 1 die. Charging gives 1 extra die. Would still be 2 dice when charging in assault and using Smash Attack.
Smash 40k6 pg 42
All of the close combat attacks, except Hammer of Wraith Attacks, of a model with this special rule are resolved at AP 2 (unless its [sic] attacking with an AP 1 weapon).
Furthermore, a model making a Smash Attack can re-roll its armour penetration rolls, but must abide by the second result.
Context: Didn't pick this one up until making this post. Spyder was assaulted by veteran squad. Spyder wounded a vet and said it was AP 2 attack. Opponent said that was only when performing a Smash Attack. Thought about it and agreed with him. I was wrong. Should've looked it up.
Fear 40k6 pg 35
At the start of each Fight sub-phase, a unit in base contact with one or more enemy models that cause Fear must take a Leadership test (called a Fear test) before any blows are struck.
Context: Vets assaulted sypder. Informed opponent they must make a Fear test. Next turns Fight sub-phase informed they had to test again. Opponent wondered if they only had to make that test once. Informed Fear test is done at the beginning of every Fight sub-phase. He wanted to make sure.