This is just a trial and error sort of guide that I've experienced positive and negative outcomes with and is in no way refined for guaranteed outcomes.
Going Q levels 1 and 3 make the damage a little higher for trading, seeing as you might not need E till the jungler on the enemy team is ready to gank. I recommend E early if they have an aggressive early game jungler. Going E level 3 or 4 means you shouldn't hug the wall in bottom lane, try being near the river with a ward covering the flank. The Caretaker's Shrine sucks, but leveling it second is just as good as leveling Magical Journey second, doesn't matter really. If you do max E second, you do have the speed advantage for allies going through, which can really make a difference in some situations, but it might be as useful as W max second.
Early game is very tricky with bard in lane. While he's new, people don't know what he does, and can over commit to trades that end up putting you behind. Bards greatest weakness is his base resists, and cool downs. Try to trade solely with Q, stunning them off of a minion or to the wall or champion if you find the opportunity and then use your meep auto. If you're out of meeps try to play it safe. Very important while laning, is the wave. Do not let the wave get out of your control, let it stay in the middle of both turrets. With bard, helping your carry kill minions under turret can be very tricky and you might end up losing more by doing so. If the lane is too pushed up, you run the risk of it freezing away from you, putting you in a bad spot if you're on blue side. Red side is more forgiving, as the red side wall in bot lane allows for a deeper escape than the blue side wall. The early magic pen and ap runes allow for a heavier auto Q combo against the carry or support, but do not trade heavily against healing supports. You will not out sustain them.
When bot turret falls, or when you feel like the enemy support is doing more roaming, try to route with the chimes and run with your jungler. Almost any jungler is good paired with bard, especially since bard can double up stun on the walls in the jungle with Q and escape almost any situation with E. Also, ganking can be fairly easy with bard, seeing as how his ultimate can easily force a summoner spell from mid lane, setup a dive, or even save your team mates in losing battles. You want about 40 chimes at around 25-35 minutes. Thats when bard kind of hits a power spike. The blue trinket is very good for Bard's mid game, seeing as how its the radius of his ult, allowing for picks on crucial targets to get objectives.
Late game is where bard might fall off, his damage isnt as potent, and his Q is just an inconvenient stun against the enemy team. But play around having his ultimate, it will really help with focusing on team fights, objectives and positioning. But if you're defending in the base with bard, you'll have a very hard time to do anything without your ult. If you are defending, try to save your ult for splitting the enemy team up, hitting either the tanks, low health targets or even the carries (1-3 people) that way you have 2.5 seconds to burst down a target and then position yourself to stun the adc or midlane/jungler before the stasis runs out.
Try to stay right next to your adc, soaking up any skill shots, but don't let yourself get low on health. If you aren't playing against vayne, or poppy, try to fight near large walls to escape if you over commit with whomever you're fighting with. If you have about 20% cool down reduction, you can really pump out stuns and allow your team to get the fights they want. I strongly recommend using your ult when you KNOW you'll get something out of it. If you waste your ult on something that wont result in a kill, then you'll lose pressure as bard. I like to save my ult against Zed, or Lissandra in particular, due to the burst potential they have on squishy carries. Don't be afraid to ult your teammates if they are getting attacked, you can really save someone from any damaging over time abilities.
Overall, bard is a very nice addition to the team compositions you can have, but he may not be as good as other supports in what he brings. His laning phase is very bad against most match-ups, but if you last till mid game, you can really bring a lot to the table for plays and picks to be made. You can't pick bard against an over aggressive bot lane like vayne thresh, or blitzcrank graves. He thrives against short ranged carries, but he also gets melted very quickly. If you can continuously stun with Q and meep auto, you should win the trades and create pressure in the bot lane. I hope this guide was informative to anyone interested in what bard does, and or interested in picking him up. Try him out in a custom match if you're new to his abilities, but also get a feel for how he plays. Thanks for reading, comments are greatly appreciated!