If you're taking TP, then just stick to sidelanes once midgame hits and TP if a teamfight starts on the map. (Hopefully someone dropped a ward nearby or minions are close)

Otherwise, try to catch waves in lanes that other people aren't in. If bot is completely empty past 20 minutes and there are minions there, consider swinging by and grabbing them. You can always leave once you get them and rejoin your team if an objective is up.

However, don't always do this. If Baron/Dragon is up, maybe stick to the 2 lanes closest to the objective (unless you have TP/are ready to use it).

He's an ADC main, but I know xFSN Saber has some good videos on how to catch waves and maximize gold once laning ends. Obviously it would be a little different for a toplaner, but you can probably get something out of watching some of his guides.