Some variations of these have been said already, but here you go...
- stack up to three inspiration points (players do hoard them, by the way)
- group checks - +2 to skill check if helped by one or two people, +5 if helped by 3 or more - has to be an action for which it is possible for people to help (not picking a lock on a small chest) - courtesy of The Angry GM
- on leveling up, if player rolls less than average on Hit Die, they get average (for less squishy PCs)
- Roll initiative at the beginning of the session so can jump right into a combat when it comes up
- if spells are copied from a found/stolen spell book into a PCs spell book, the spells disappear from the original spell book (as if copied from a scroll). This caused the two wizard players in our group to negotiate a bit when splitting up the spells.
- implement some skill checks ala Matt Colville's method:
Skill Challenges! Running the Game #21 - YouTube
- create "graduated success/failure" on some other skill checks - you'll need to prep this ahead of time accordingly. For example, when picking a complex lock, 20+ = immediate success 15-19 = takes 1 minute, 10-14 = takes 2 minutes and is not quiet, 5-9, takes 5 minutes and makes considerable noise, <5 takes 10 minutes and makes considerable noise and breaks two lock picks