Polite Verbs (-masu form)

I think ます form is probably the most common first-taught form for Japanese verbs in standard classes, likely because it's the most useful if you're visiting Japan. I've said this in the past, but I don't agree with only teaching ます form. Rather, I think students should first understand dictionary form and learn to conjugate from there, because it makes subsequent conjugations that much easier.

Anyway, my knowledge of how to obtain the verb stem will come in handy here. To reach the polite form for both ichidan and godan verbs, I simply take the stem of the verb and attach ます for positive or ません for negative. That's it.

する and 来る are already in "exception form" with the stems し and き, so they simply become します and きます. So really, there aren't exceptions for ます form because the exceptions are already taken care of with the verb stem.

食べる  -  食べます
走る  -  走ります
入る  -  入ります
書く  -  書きます
出る  -  出ます
知る  -  知ります

There's another way that verb stems are useful. If I want to connect or string together two verbs, I simply use the stem of the "target" verb and add に to it, then add the second verb. It's hard to explain so examples will make sense of it.

学びに見る  -  watch to learn
見つけに走る  -  run to find
買いに行く  -  go to buy

It's the opposite of English, but frankly, it makes sense with the other Japanese grammar I've learned thus far. It'd feel wrong the other way.

Credit goes to Tae Kim's lesson seen here.