Continue practicing popping the yo-yo into the air while whipping the string around it.
When you’re able to hop the yo-yo up and whip the string around the yo-yo without the yo-yo going anywhere but up or down, you are ready to start putting your freehand index finger into the loop you are whipping around.
This video will break down how to perform a harder yo-yo trick referred to as Brent Stole. It’s basically a laceration into a green triangle. It and the reverse Brent Stole are very popular freestyle tricks.