Tips for carrying a new team.

Ive been playing league since the zac release (about 6 years I think) and I've started up a group with several of my friends. Obviously, being new, they all kind of suck. This is totally ok and I was expecting it from the start, but I could use some tips to better carry games. Because currently I can play Orianna, go 25/2, roam successfully all game, ult the entire enemy team late-game, and still lose. Any tips you guys have would be appreciated