If you roll a natural 20 on your initiative, you gain advantage for your first attack. If you roll a natural 1 you get a disadvantage on your first attack. This is so those good and bad rolls arent wasted on positioning
Players can use one inspiration (only if its granted by the DM) to re-roll a saving throw. This includes death saving throws. Other than this inspiration can be used normally to add 1d4 to any non damage roll.
All shopping for non story related or magical items can happen in between sessions (i.e. getting more ammo, buying armor, new weapons etc.)
When you level up and are rolling for Hit Points, roll with advantage. This means roll 2 dice and take the highest. This is to significantly decrease the chance of rolling a 1 which lets face it sucks!