見よう/見ろ　ａｎｄ　しよう/しろ
 

The volitional form of 見る and する confuses me.

I learned that 見よう and しよう are the volitional form of 見る and する.

But I often hear people say やってみろ and 勝手にしろ...

Why not やってみよう and 勝手にしよう？

Your talking about 2 different forms.
見よう - Volitional
見ろ - Imperative

Edit:
You may also see 見よ as an imperative but from what I know this is a written form.

You do? I rarely do here in Japan as those are pretty vulgar forms. I wonder what kind of people you're surrounded by.

If I may add, the みろ part of やってみろ has nothing to do with 見ろ. 見る and みる are two different words.

To clarify for someone who hasn't seen discussion on this before, 見る means "to look/see." みる means "to try out." やってみる means to "do something [to see what it is like]." 食べてみる means "eat something [to see what it tastes like]." Etc. The use of kanji for みる there is 100% incorrect. It's essentially like writing 貝社 instead of 会社 for "company."

Thanks all! Now I understand the difference between 見る and みる

But I still don't understand しよう and しろ
Are they both from　する？

Doesn't your dictionary have a list of conjugations for the basic verbs?

する infinitive
しよう volitional
しろ imperative

する is THE most frequently used Japanese verb. You will need to be able to conjugate it freely.

And in case OP doesn't know these linguistics terms, "volitional" is "to be going to do XXX" and "imperative" is "Do XX!"

Basically, volitional is a suggestion/intention, and imperative is a command.