These are all of the different ways I can think of (I might have missed some) of how to request something in Japanese in no real particular order:
しろ
して
してくれる
してくれ
してくれて
してください
しなさい
After some time of learning these conjugations I stumbled across various sentences, usually in video games or recipes, that would use the base dictionary form of a verb, rather than the above, to ask me to do something. I have the feeling it also applies to telling myself to do something (in an alarm for example) because saying 牛乳を買って feels a bit odd as opposed to saying 牛乳を買う, but I'm not entirely sure.
Here are a few more examples:
-「信用して」と彼は言った。
- できれば、数月に旅行へ出ていくときにうちのワンちゃんの面倒を見て下さい。- スポンジを作ります。ビターチョコレートを刻み、湯せんで溶かします。
- ノーマルモードをクリアする
I imagine the latter doesn't really have much to do with requesting at all and is more just used for instructions, but I'd just like to have a more concrete definition of the difference/usages.