If the first wall of learning Japanese is Hiragana and Katakana. Then Verbs are definitely comes after.

I may come back and write about how to learn them, but following are some resources I've found useful.

OJAD search can help you with looking up a verb's conjugation forms.

This site 基本動詞ハンドブック is a high quality content put together by Acedemic folks. 110 common verbs with why, examples, and illustrations. They also explain similar verbs well and its nuances.