How Can I close out Games?

Im not that great of a LoL player but I wanna get better. I was in SIlver for awhile but i stopped playing for a bit and LP decayed me back into bronze before the end of the season.

Anyways, I find that in the beginning of games, I tend to do well and get a few kills and get ahead, and a lot of times ill be pretty strong throughout the game. But in those games where you have a feeder or your team just isnt "clicking" (Winning teamfights, etc) what can i do as a solo que player with my lead to close out the game early before its too late?

And usually one the other team gets too strong, theyll kill me a lot and make my score look bad, which i guess I need to still work on not dying in these late game times.

But could anyone give me advice on what I should do to close out these games?

Like should i be pushing one lane hard? pushing all lanes? helping my team and follow them wherever they go ? Split push ad try to get turrets?

What should i be focusing on most and doing to give my team the best chance of closing the game early while we are ahead?

Thanks in advance.