Have a whiteboard to write down the monster's defenses. This way, players can roll their attack and damage while it isn't their turn and know if they hit or not so they can just say so when it comes to their turn.
Have one seasoned player sit next to you. This player can help ...
Both of these are excellent tips.
NEVER allow people to get books out during a fight. Use power cards and make ad hoc rulings, then look stuff up between sessions and come to a consensus.
In general, I don't allow books at the table unless we are in town and shopping.
I also record the defenses of my players on the whiteboard, as well as everyone's initiative.
Plan out each monster's action and roll attacks while the player are going. On the monster's turn you only need to move the miniatures, say 'you take 10 damage, you take 8 and are prone', remove conditions that you saved for, and instruct the next player to go.
Don't roll damage, just pick a random number close to average (average is usually [min + max]/2). I only ever roll d20s when I DM.
If one player is taking awhile on their turn, inform the next player to start getting ready. Don't rush newer players, it rarely speeds things up and makes people cranky. Seat a helpful player beside a confused one.
Its nice to have an experienced player sit beside you and give them privileges and responsibilities. You could let them help you track combat. If two players are going at once you can handle one while your wingman handles the other. You need to let this player in on monster HP etc though.
Make sure to have a card, paper, or computer screen showing all the monsters' stats during every fight, flipping through pages of the monster manual is generally too slow.