he's not that hard to grasp, at least mechanically
bard is mostly decision making because his spells are so versatile. use Q and meeps to kite, engage and stun people. you can't always aim for the stun; if repositioning is dangerous, the slow is good enough. you'll always get max CDR so you can use it fairly liberally
W is good for charging in lane or if you're defending a siege so that teammates don't need to go back if they eat poke. Use its instant cast for a clutch heal and MS boost, good for running away or saving people.
E is mobility. use it to run away and stun anyone who follows through it, use it for chasing or unusual gank patterns. very flexible spell, but it can put you in serious trouble if an enemy slips past at a bad time
R is probably the hardest part of his kit for people to grasp because there's unlimited ways you can use it. it's not amazing for engage unless you NEED the stasis to set up a wombo, but it's great at giving everyone time to reposition, which lets you make saves, set up a stun for kills, chase down runaways. It's great for force-resetting the big objectives like Dragon and Baron, since they'll recover HP while frozen. If enemies are trying to take it earlier on, this can be what forces them to back or if your team is close enough, lets you collapse on them. if you use it to defend a tower, don't ult the tower (most of the time) ult the minion wave so that it aggros the champion, or ult the champion so that you can jump on him (the former is more likely, since minions are predictable). ulting only the tower won't really do anything; it keeps it up a few seconds longer, but the minion wave is still there and the enemy will probably stick around and take it anyway.
max Q always, W and E is mostly situational. I like to max W because I build more AP on him than others, but maxing E second gives you a better MS boost for allies and a lower cooldown, where W just improves the base heal iirc.
play him like an asshole; don't ever commit too hard to fights unless you're setting up a collapse, just skirt around and throw out Qs and meeps and fish for stuns. It's a good idea to stay near walls (not always) so you can make a quick getaway, but you can cast it from a pretty far range if you'd rather throw it out near an ally.
i don't think a lot of people do this but if I happen to be really ahead, I build 
after my support item (sometimes before, it depends on how much gold I have/whether I need the FQC active immediately) because it gives him a lot of good stats both up front and for late game where he's strongest.
a safer build is something like 
. Decent chunk of stats, you're durable and you provide a lot of utility. I don't like 
at all but a lot of people buy it on him; if you like it, it's not a terrible purchase. 
are also good purchases due to his immense roaming power; Bard can E to a lane, drop one of these down and run back out to join his team; it's a very underrated strat IMO.
don't be afraid to buy damage if you're ahead. Bard has monstrous synergy with AP items like 
and 
, and 
is great in conjunction with your ultimate to annoy people who are chasing you. Really, all you need is a Lich Bane and some magic penetration (Sorcery Shoes) and you can pretty handily nuke squishy targets.
get chimes whenever it's safe; leaving your ADC, while sometimes tempting depending on their personality, is not generally a good idea unless they're a safe ADC like Caitlyn or Ezreal, someone who can disengage or self-peel while you come back. I wouldn't extend too far past river if you're in lane unless your carry is backing, is returning to lane, or you're going to make your journey more worth their 2v1 with a gank or at least warding further up river. If you absolutely need to refill on mana, it's always a good idea to ping or type it out in chat before you leave, so that they know to play it safe for a few seconds. you should aim to get multiple chimes if you leave for them; it speeds up your return and it lets you keep going, but if you can only get one or two I wouldn't go for it.
Go 18 into cunning always and take Thunderlord's for the additional burst. I prefer putting my 12 into resolve for the tank stats and self-healing boost, but if you plan on building a chunk of AP, put your 12 into offense. Your meeps are considered a spell, so they're affected by the damage amp in Ferocity and both meeps and Q slow/stun, so they get further amped by Oppressor.
Is a good combo with 
. Theyre both fast out of combat, they can roam perfectly together, both have a need to do it. Bard can help his ADC sustain in lane with his Ws, and his jungler gets an easy first clear as you should take W first.
is SO MUCH BETTER than 
TRUST ME. ** <<TAKE THAT ADVICE PLEASE**
