Perform 3 sets of plate pushaways, fork putdowns, and fridge door closes. Repeat daily.
Pardon the sensationalistic blog title, but I'm trying to mimic YouTube. Most of your typical ab routines are a waste of time. You can't spot reduce body fat. Period. Doing chest exercises won't burn fat off your pecs, and doing ab exercises won't burn fat from your stomach. Belly fat loss is the result of a caloric deficit over time that burns fat from your entire body, eventually catching up with your stomach. No amount of ab training on its own is going to get you a six pack. You just need to work your abs as you would any any other body part. For me that means 1) planks and 2) hanging leg raises done twice a week at the gym.
But getting down to a sufficiently low body fat is mainly an issue of diet combined with building up the abs.
Train hard but train smart!