It's evident that Toxrill, the Corrosive is a slow card, but its high power makes you want to play it no matter what. All that you need to do is find a way to speed up its counter effect and token production.
In this case players will need a consistent Porliferate engine, such as Yawgmoth, Thran Physician or similar, in order to increase the number of counters. You may also need to make a copy of Toxrill himself to double the speed further on.
Regardless of your strategy here, Toxrill is a solid commander card.