If your tank is relatively new, then reaching a high nitrate level is going to take time even if you are feeding heavily. Don't do water changes and make sure there are a few fish in the tank. Nitrates will rise when you have healthy colonies of bacteria converting ammonia and nitrite from the fish waste into nitrate. Meaning that you'll want to be careful with the heavy feeding, because you could just be increasing your ammonia levels with no bacteria in the tank to actually convert it into safer chemicals such as nitrate.
Either way, be careful what you wish for. High nitrate usually just ends up in nuisance algae problems. While slightly elevated levels have been shown to improve coral growth, I'd argue that you're much better off just ensuring that calcium and alkalinity as well as other parameters are at a good level to achieve that goal. I've seen many highly successful tanks that operate with zero nitrates. Most people are more focused on bringing nitrate down, not up.