I’ve been running 4e for a while now, and here’s what I’ve learned about speeding up combat:
1) Each player has more options in each round. If each player looks over each and every option as it comes to their turn, and not before, slowness ensues.
2) Having cards for each power (there are many nice ones available to print out) saves a lot of time, because you can turn over your daily and encounter powers as they get used, thus reducing the number of options you have to choose from.
3) Monsters have more hit points – the idea is that each PC will get a chance to do something to them before they go down. So if you plan to have more than 2-3 enemies for the PCs to fight, consider using minions to pad out the rest, since they go down much quicker, but allow you to retain the tactical interest of a mob.
4) Dice matter a lot more, so if someone is having an off night, things will go longer. One way to help with this is to make sure your enemies have a reasonable AC. Even though the XP totals might work out, monsters that are 2-3 levels higher than the PCs are often quite hard to hit, which can slow things down. Save those for special occasions.
5) Keeping track of conditions is better in 4e in that they typically only last one round, rather than dX. That said, there are often more conditions to keep track of. I’ve been using the little Alea Tools magnets to keep track of conditions, but condition cards that can be flipped over once someone saves might work even better.
6) I agree with Jonathon’s comment in that if your group isn’t used to working as a team, and considering how their actions affect everyone else, it can slow things down. After 3-4 sessions, my group really got into the groove, and started really laying the hammer down. So, one suggestion might be to run the encounters toward the bottom of the
XP range until your group gets in sync with their character set.
7) In general, they removed a lot of the aspects of combat that were slow and didn’t add tactical/RP interest. However, they added a lot of tactical options, and powers that convey more of the spirit of each class. But it’s still your job as DM to keep an eye on your group, and to present them a mix of encounters that they enjoy. If they aren’t as interested in the complex tactical aspects, then send them simpler monsters, and/or ignore what’s not working for them. I’ve often found that you can use say, a poison attack once or twice to get people the flavor, and then let it go for the rest of the battle to speed things up.
8) For newer players, I often will only give them one power card per level to worry about. Some players will be happy with that forever. Others might want to branch out into more options as time goes on.
9) Mixing in the RP with the combat is another way to make things more interesting. You might have three groups of enemies, and they are chasing the PCs around, rather than just having a slugfest in a room.
10) If you are running a published scenario, don’t be afraid to scale back the encounters in terms of numbers of enemies to speed things up…