Solo-queue Olaf?

I recently picked up Olaf and wanted some advice on improving my game. I am hovering around 60%WR at high gold / low plat, but noticed I lose a lot of games I should be able to carry. How can I close out games before I fall off if my team is not moving on objectives? Should I split push or group?

Gold advantage seems to matter less and less the longer the game goes on (20-25min>). Team fights are hit or miss, I either get focused down before doing anything or wreck their back line. And if I anticipate the game will go on long should I be itemizing more damage or survivability? Late game I feel like a meat shield that's just there to disrupt the other team.

I see most top Olaf players build Black Cleaver into Warrior Enchantment followed by situational items (Randuins, Steraks, GA, etc), but their playing at a higher level, so wouldn't more damage make sense if I am focused on plat/gold solo-queue?