There is nothing worse in RPG combat than a long break, when players are checking rules, thinking and discussing what to do next and so on…
As I mentioned in FC: A duel and a slaughter, players should feel the atmosphere of a battle and react as quick as possible. Today, I will give you some practical tips on how to achieve that, make combat quicker and more enjoyable at the same time.

Initiative
Some may disagree with me here, but I believe making initiative public is a good idea. After the first round players will know the turn order anyway, so there is no point in hiding it. There are few useful ways to keep track of initiative and also make the combat go more smoothly:
1. Use initiative cards. Sheets of paper with characters’ names on them and also few sheets for their enemies. Once you know the initiative, put the cards into a desired order.
2. Write initiative on a whiteboard, if you use one. This will allow everyone to see who’s next and how long they have to wait for their next turn.
3. Use some combat-initiative computer tracker if you are using a laptop. However, if you use computer, you can always write the initiative order in a notepad or Word or whatever…
4. Inform each of the players that their going to be next in the initiative, “It’s Michal’s turn, and Derek is going next.”
5. Roll the initiative for each group of enemies, not for each single skeleton… One initiative for a villain, one for his minions, one for his female assistant.

Turn Length
I mentioned the idea of limiting time for a turn in A duel and a slaughter post. Anyway, it is a good idea to limit the time each of the players have to decide what their actions would be. I suggest a time of 20-30 sec. Also, keep in mind that it is a time to decide what they are going to do, not to roll the dices etc. This is especially important in 4e, because it seems that players roll more dices in this edition than they used to be (one of my players, when using a power, rolls seven dices).
As always, it is good to discuss the idea with your players, so that everyone knows that they should hurry with their turns.

Get help from players not involved in the combat
This will prevent them from getting bored, and also speed up the combat. You can decide who is being attacked and let the player roll dices, or you can let him/her take full control over a single monster.