Um, what I do is i try to stop the bleeding as much as possible. On ali, I try to save their life and maybe she will be relevant. Like the other day, I had a jinx and she was bad at laning but i kept her alive, and tried to peel for her even though i had a bad game and didnt do a great job. She carried our sorry asses lol.
On Bard, he makes it easy, you can do so much, drop heals, go roam with the Jungle. So often if there's a jungle skirmish in river I'm involved half the time.
Sona, you need to poke the other laner to keep them off your adc, and use your heals and the aoe shield aura to negate their dmg before it lands. I'm getting a lot better roaming on Sona. Her power cord tempo is real good for ganks.
Junglers are your best friend, running with them to deep ward, control enemy buffs, gank, etc
Not every game is winneable thou