Explain to your team what you're doing.
A lot of times when I play as Jax, I get to the point where I can easily 1v1 any player on their team. And sometimes, when I'm fed, I can 2v1 anyone on their team. When we get to this point, if my 4 teammates play smart, we can win the game no matter what.
All it takes is my 4 teammates knowing when and when not to engage.
They can handle a 4v5 if they're under the turret. They can handle a 4v4 if they're under a turret. If it's 4v3 or better in favor of my team, they need to be pressing the lane their in and press that advantage (otherwise, 3 or more are headed my way and I have to retreat).
But too often, I get teams that say "Well if Jax can handle a 2v1, why can't we handle a 5v4?" And the problem is, when I'm trying to split push, it's when we don't have an advantage in team fights because I'm the only fed player, and whether we team fight or I split push, I'm still the focus. Split pushing just forces the enemy to split their team. My team can defend 4 or 5 enemies if they stay under a friendly turret, and if the enemies are keeping 4 or 5 of their team there, they haven't sent enough to stop me from taking out turrets twice as fast as they're taking out ours.