I'm currently using what I call a combat escalation system in my campaign. It seems to have worked out pretty well so far. Essentially:
1. After the first round of combat, everyone (PCs and monsters) gains a +1 bonus to damage. This increases by +1 at the start of each subsequent round.To help keep track of the variable bonuses, I made up a set of cards (attached) and at the start of each combat round, I just put the card for the new combat round on the table.
2. After the bonus to damage rolls increases to +2 or more, everyone gains a bonus to attack rolls equal to half the bonus to damage.
3. After the bonus to attack rolls increases to +2 or more, everyone's crit range increases by half the bonus to attack rolls.
Ah I remember this system. I'm glad to hear you made cards and did it that way, I'm sure its a lot easier to track!