Bard is a rather difficult champion, especially if you get greedy. as a support he lacks the engage and disengage needed to be effective early game as his portal doesn't provide a good path on bot. The best way to play bard that I've found is to build him tanky with only some AP.

The important thing to remember is that chances are you adc is going to be playing defensive for the most part if you leave too much and your lane will become the enemy jungle's best friend. for the most part this means you cant roam farther than your corner of the world, which can be bad if the chimes are spawning only in enemy jungle.

The runes I find work best are tankier runes. you could also take some hybrid pen runes. This is because his attack damage from his meeps can become quite strong in the late game.

Movement speed runes are unnecessary.

a lot of bard guides i see have him grabbing boots of mobility, which makes no sense to me, sure it helps you run and grab your chimes and get back faster but if you're like me and build sun-fire cape, your going to have that removed every time you pass to close to a jungle camp. so i build boots of swiftness which allows for more movement speed and better escape potential as you are more likely to out run enemies.

I build rod of ages for one reason, sustain. if you leave lane often you need to be sure that you can engage properly with out just being popped by an enemy you might run into if you you accidentally face check them in the bushes when chiming. rod of ages early will make sure you keep up health wise when you aren't getting enough gold, which shouldn't be too much of a problem but it helps.

Pros:
-Mobility is high later in the game,
-high possibility to lock down turrets and kills by holding people down or speeding up your team with heals.
- can be a lot of fun
Cons:
-You get focused a lot
- You leave your bot lane with a 2v1 lane
- very difficult to play