I'll take care of it myself.
Take care of your own affairs yourself.
Do something about that yourself.
Do it for yourself.
Go about your business.
自分でやりなさい
自分でおやり!
Do it by yourself.
自己流にやる.
自業自得だよ。
自業自得だよ。
自業自得だよ。
You made your bed.
Make sure that you do it yourself.
I will do it myself.
Go do your homework.
Do it by yourself.
You should do that.
ぜひそれをやってみなさい。