Don't do it.

Suruna : Don't do it.
suru : do
(shi-nai,shi-masu,suru,suru-toki,sure-ba,shiro,shiyou,shita)
suru+na : don't do (imperative)
shi-nai + de : don't do (imperative)

PatternC of verb conjugation + "na" means negative imperative sentence.
And patternA of verb conjugation +"nai"+"de" means same.

Miruna : Don't look.
miru : see, look, watch
(mi-nai,mi-masu,miru,miru-toki,mire-ba,miro,miyou,mita)
miru+na : don't look,don't watch
mi-nai+de : don't look, don't watch

"+na" pattern is very strong phrase.
If you want to say more politely, "kudasai" should be added after "-nai+de" pattern.

Minaide kudasai. : Don't look please.
Shinaide kudasai : Don't do (it) please.

In the case that the object word is needed, the object word is put at top of the sentense.

Watashi o minaide kudasai. : me, don't look ,please : Don't look at me ,please.
Hon o yomanaide kudasai. : book , don't read,please : Don't read a book, please.