I have been learning the verb list for the N4 exam but I do not know how to tell the group of a verb. Until know I have memorized them by heart. Nevertheless I have still trouble to tell the group of a verb because I can't memorize them all. I would have wanted whether there is a systematic method so as to know the group of a verb, could you help me on that?

According to my textbook:

* いきます belongs to group I
* ねます  belongs to group II
* きます　belongs to group III