#Brutes And Soldiers slow down combat

#Utilize Leaders with minions, artillery, skirmishers, lurkers and controllers

#There is no magic formula to use every time

#Mix up the combats by adding dangers to the arena/dungeon in which they occur

#Create Solos that act and behave like the boss monsters they are meant to be

#Create recurring villains that also fight in encounters†

Brutes And Soldiers slow down combat

Utilize Leaders with minions, artillery, skirmishers, lurkers and controllers

There is no magic formula to use every time

Mix up the combats by adding dangers to the arena/dungeon in which they occur

Create Solos that act and behave like the boss monsters they are meant to be

Create recurring villains that also fight in encounters†

Brutes And Soldiers slow down combat

Utilize Leaders with minions, artillery, skirmishers, lurkers and controllers

There is no magic formula to use every time

Mix up the combats by adding dangers to the arena/dungeon in which they occur

Create Solos that act and behave like the boss monsters they are meant to be

1. Solo's act on multiple initiatives. Create solos that have 2 or 3 initiatives during which they can do 1 or 2 specific types of actions, but not a whole turn. Suddenly Solos can interact with the party throughout a round rather than having 1 big solo turn than the rest of the party and so on. Giving each initiative roll different modifiers (+5,+10, +15) will help to ensure they are staggered or just giving fixed initiative values such as 10, 15, 20).
2. Solo's are made up of different "parts." Take those different initiatives you've built in and they literally correspond to different parts of the solo monster. For the example you gave the dragon's tail, claws and head would each be a part of the monster. The head would have the best Defenses and HP because if it went first the boss would essentially be defeated, but players could destroy the tail or legs in the fight costing the monster those abilities and the initiatives linked with them.
3. Solo monsters have "stages." Solo monsters transform as they are defeated throughout the fight. That wizard the party fought takes an immediate reaction when his HP hits bloodied, transforming into an abomination by drinking a potion/uttering a spell. Where he was a wizened wizard throwing spells before, now he is an 8 foot tall hulking mass of muscles and horns seeking to smash the party.

Create recurring villains that also fight in encounters†

#Brutes And Soldiers slow down combat

#Utilize Leaders with minions, artillery, skirmishers, lurkers and controllers

#There is no magic formula to use every time

#Mix up the combats by adding dangers to the arena/dungeon in which they occur

#Create Solos that act and behave like the boss monsters they are meant to be

1. Solos act on multiple initiatives. Create solos that have 2 or 3 initiatives during which they can do 1 or 2 specific types of actions, but not a whole turn. Suddenly Solos can interact with the party throughout a round rather than having 1 big solo turn than the rest of the party and so on. Giving each initiative roll different modifiers (+5,+10, +15) will help to ensure they are staggered or just giving fixed initiative values such as 10, 15, 20).
2. Solos are made up of different "parts." Take those different initiatives you've built in and they literally correspond to different parts of the solo monster. For the example you gave the dragon's tail, claws and head would each be a part of the monster. The head would have the best Defenses and HP because if it went first the boss would essentially be defeated, but players could destroy the tail or legs in the fight costing the monster those abilities and the initiatives linked with them.
3. Solo monsters have "stages." Solo monsters transform as they are defeated throughout the fight. That wizard the party fought takes an immediate reaction when his HP hits bloodied, transforming into an abomination by drinking a potion/uttering a spell. Where he was a wizened wizard throwing spells before, now he is an 8 foot tall hulking mass of muscles and horns seeking to smash the party.

#Create recurring villains that also fight in encounters†

I can't give you a template, such as 1 leader, 5 minions, a soldier, an artillery, and a controller, and say that it will work every time. Even if it did, by the very nature of repetition it would become boring and stale for your players. The beauty of the XP balancing system in 4e is that you can mix things up and still make a balanced encounter (provided you use monsters within 1 level of the party level: -1, same or +1). There could be an artillery heavy ambush or multiple leaders with lots of minions ordering them around and it would work just as much as the above formula I just gave you.

The Angry Dm has an excellent series of posts (Parts: 1, 2, 3, 4) detailing all of these issues and his proposed solutions (which I totally agree with). I've summed some of them up below, but be sure to check out what he's written.

I can't give you a template, such as 1 leader, 5 minions, a soldier, an artillery, and a controller, and say that it will work every time. Even if it did, by the very nature of repetition it would become boring and stale for your players. The beauty of the XP balancing system in 4e is that you can mix things up and still make a balanced encounter (provided you use monsters within 1 level of the party level: -1, same or +1). There could be an artillery heavy ambush or multiple leaders ordering around lots of minions and it would work just as much as the above formula I just gave you.

The Angry GM has an excellent series of posts (Parts: 1, 2, 3, 4) detailing all of these issues and his proposed solutions (which I totally agree with). I've summed some of them up below, but be sure to check out what he's written.