Hero Guide

Heroes:

Barbarian King: the Barbarian king is available to unlock as a hero in the game at townhall 7. He can soak up a lot of damage and deal out a lot as well. 

The Archer Queen: the Archer Queen is available for unlock at townhall 9. She cannot soak up as much damage as the King, but she is a range unit and if you place her properly behind your army then defenses will not focus on her and she will deal out devastating damage.

The most common Mistakes I see that inexperienced players make with regards to heroes:

They max them at townhall 7 and or 8. Once your base is good enough the heroes will start to level up on their own, what I mean by this is:

At townhall 7 with the new update you do get a dark elixir drill. However it is pointless to try and get your king maxed out at level 7 townhall, it is more difficult to get dark elixir with only one drill. You will progress much faster in the game if you just go to townhall 8 after your defenses and walls are maxed and then work on upgrading your Barbarian King.

At townhall 8 you should be able to upgrade your king a few more times due to the fact that you will be able to get two dark elixir drills. By the time I maxed townhall 8 my king was level 8. This is largely due to the fact that as soon as I got to townhall 8 I maxed my dark drill to level 3. This is something I highly recommend. Again there is no point in maxing your king at townhall 8 because you will make way more dark elixir at townhall 9 then you ever made at townhall 8 in a fairly short period of time. This is largely due to the fact your dark elixir drills wont be limited to level three, they can be upgraded to level six.

The most common mistakes with heroes made by experienced players:

I see this all the time, the people that attack our war bases, people in my own clan, everyone does it! The mistake that players make is that once their barbarian king or queen reaches at least level 5, they don't know when to rage it. DO NOT RAGE YOUR KING OR QUEEN BEFORE THEY GET INJURED. When you rage your king or queen the rage not only makes them more powerful but it heals them as well.

The second most common mistake I see is hero placement in battle. When the clan castle troops come out, whatever you do, do not panic and place your barbarian king, and whatever you do definitely do not place your archer queen. The clan castle troops will take care of your heroes in no time. There are much better ways to kill clan castle troops. If you are not sure of good ways to lure out the clan castle or take care of the troops have a look at my post on Clan Castles. Not only do players make the mistake of placing heroes before the clan castle troops are taken care of, they also place them at the front of their attacking assault. You should never place your Barbarian King before you place troops like golems, pekkas and giants. This is because your Barbarian King is your strongest attacker and even though he can take a lot of damage, you want to keep the defenses from shooting at him for as long as possible.