Poliwag, do you have any experience with pacman frogs? I also plan to breed in the future, currently I have 2 years+ of experience with these frogs and plan to get atleast 10 more years under my belt before I even attempt it.
You need two healthy frogs, a rainchamber, a ton of space, money and time.

edit: yes Truffs, daily water changes, even twice a day as grif pointed out, and daily food. Also, you have to make sure you'l be able to sell your offspring, while 5 pacman frogs might be easy to sell, if you breed 150 cranwelli's, your going to be housing some of them for quite a while.... $_$