When rolling a Death Save, a player must roll it in secret, and must keep the result secret from the other players.
Heroic Hit Points
When rolling hit points gained during level advancement, your minimum result is 1/2 your maximum possible result, plus your Con modifier.
Minions have only one hit point. A missed attack never damages a minion. When a minion is subjected to an effect that allows it to make a saving throw to take only half damage, it instead takes no damage if it succeeds on the saving throw. Minions always deal average damage. The DM will always reveal and remind players which enemies are minions and which are not.
When you score a critical hit, roll for damage normally. Then determine the maximum damage you can roll with your attack before applying any modifiers. Combine the maximum result with your rolled damage, and then add any modifiers. This is your critical hit damage.
Example: A character wielding a longsword with 16 Strength who scores a critical hit would deal 8 + 1d8 + 3 (STR mod) damage.
When you would normally roll one or more dice to restore hit points with a Potion, you instead use the highest number possible for each die. For example, instead of regaining 2d4+2 hit points when you drink a Potion of Healing, you regain 10. Potion of Greater Healing = 20 hp, Potion of Superior Healing = 40 hp.
If a character is proficient in a skill or tool use, he or she cannot score a skill check result less than 10 + proficiency modifier + attribute modifier. This applies to specialization as well (2x proficiency modifier). Other modifiers do not affect this threshold. A character may always choose to "take ten" instead of rolling, taking the minimum result.
Example: Aria has proficiency with Arcana, a proficiency bonus of +3, and an Intelligence modifier of +4. When attempting to recall information, she rolls a 3, adding her bonuses to get a result of 10. Since she's proficient in this skill, however, her result is automatically adjusted to 17..