Preface:
ETC is the greatest bard in the land. I have played over 600 games of ETC. He is my favorite hero. This pseudo-support build is my favorite way to play him. ETC never gets impressive damage numbers, so instead I use him as the ultimate support tank. setting up kills for your team and denying the enemy team of their own kills.

Disclaimer: With this build you trade-off defensive talents in order to provide area of effect healing. I do not recommend this build in a solo tank situation. However, I have used ETC as the solo support and solo tank in Quickmatch.
The key weakness of the area of effect healing is the limited range. for this reason, you will get the greatest effect out of this build when your team consists of 3+ melee characters.

Early Game

At this stage, you want to try to setup early kills for your team. If all lanes are being soaked, then take the opportunity to roam and try to gank over extended enemies. ETC is weak at taking camps, If their are no opportunities for ganks, then just soak in lane and allow other team mates to capture mercenaries.

Mid Game - Late Game

At this stage, you will ideally be traveling with your team. Your strengths are in peeling for your team and setting up kills on out of position enemies. With this build you will have excellent sustain for longer team fights with guitar hero, but you will have to be wary of being bursted down.

Lvl 1	Prog Rock scales extremely well the later the game goes on. With diligent globe gathering you should expect 30%-50% additional to your base healing. In fringe cases of 25+ minute games, it is possible for prog rock healing to surpass the base healing amount.
Lvl 4	Double-Necked-Guitar makes you much better at catching fleeing opponents or dodging skill shots. It is easily the strongest talent at this tier.
Lvl 7	Loud Speakers gives face melt a huge radius. With this talent choice you will be able to completely isolate an enemy or disengage from a fight. Note: This talent tier is a flexible pick and largely comes down to play style and game state. I feel all options at this tier are viable for this build.
Lvl 10	Mosh Pit is ETC's most impactful Heroic. It is a 4 second channeled stun. Hitting 3 or more people with a full duration mosh pit is usually enough to decisively win the team fight.
Lvl 13	Groupies is the backbone of this build. You can now heal your teammates. The healing range is the same as your Rockstar trait . You will need to stay close to your allies to heal them up. This ability is enhanced by your globe stacks picked up from Prog Rock .
Lvl 16	Echo Pedal provides you with the aoe damage you wish you had during the lane phase. It still has enormous value as you can now effectively finish off low health opponents and have better dueling ability. Note: Previously I used speed metal at this tier, however with the amount of slows and chase heroes in the game speed metal feels obsolete.
Lvl 20 (Primary)	Storm Shield is usually only a support talent. Take this talent and complete your transformation to support tank.
Lvl 20 (Secondary)	Tour Bus if nobody on your team is taking damage and you feel like storm shield is a waste. This talent effectively increases your moshpit duration to 6 seconds and allows you to reposition if you missed your mark or another enemy steps into range while you are moshing.

Q	Aim so that you will land behind your target with this ability, if you are coming in from an angle, then just try to clip them in front of their retreat path. This will allow you to reposition and body block or face melt at a favorable angle. Can be used to help with waveclear.
W	Use this when you want to create space between you and the enemy. Use in conjuction with Q to push enemies into your team mates for easy kills. Avoid using face melt for waveclear, especially if you are in lane with somebody else. Splitting up creeps makes it harder for most other heroes to clear the lane.
E	Use this as often as you can while in combat, even if you are still close to full health, this is your cheapest way to make use of your trait
R	Landing a good Mosh takes a lot of patience, and more importantly requires your team to follow up. If you try to go for a full distance slide into a group of 5 enemies, you are going to get stunned and blown up before your team can even react. You need to to be in a flank position or waiting for the enemy to over extend, then slide into them to setup. I find that my most successful Moshes happen midway through a team fight, after the enemy has gotten caught up in the fight and your team is already committed. Often times before a fight, teams will avoid being anywhere near ETC. After the fight starts, you will notice that they lapse in positioning. It also helps to identify who has stuns available on the enemy team, avoid using your mosh while they are still in the fight, or alternatively you can target them specifically and catch them in your mosh.

Trait

When pushing structures or taking camps, try to position yourself close to your allies before using an ability so that they can also make use of the 20% attack speed bonus. giving the bonus to all of your allies will speed things along. In general I try to space out using W and E to keep everybody's attack speed up as long as I can.