The imperative mood is how we express commands, give instructions, ask people to do something and to make suggestions. Depending on what the situation is there are different ways to say what you want to, just like every other thing we say.
The three forms
The imperative mood can be split into three categories based on the person addressed.
The du form
When addressing someone you know well you use this form. Refrain from using this form if you do not know the person well and have been encouraged to use it.
Usually we simply add an e to the end of the verb, but in informal German we often leave it out unless the verb ends in a d or t.
Fahr nach Haus.
Then you have to keep the e. If the verb undergoes a stem change you should always leave out the e.
The ihr form
When addressing a group of people in an informal manner you will be using this form.
With this form you will use the same form of the verb that you use in the present tense with ihr.
The Sie form
This form is to be use in formal situations and whenever you are uncertain which form to use.
In this form you will use the Present tense Sie form. This is also the only form in which you will be using the pronoun.
Laufen Sie da.
Formulating the Imperative
In the imperative mood, the verb is placed at the end of the sentence, unless it is used in written instructions. In that case the verb is placed at the end of the sentence.
Depending on how you are using this mood you can either use a full stop or an exclamation mark.
Usually if you want to ask in a polite way you will use a full stop. You can even bend your voice a bit in the end like you would at the end of a question.
Some verbs can be split into two parts. In this case the stem of the verb is placed first in the sentence and the prefix last. The infinitve of the verb in its unsplit form will be shown in brackets.
Ruf mich an! (anrufen)
Rufen Sie sich an! (anrufen)
When you look into the mirror you will see a reflection of yourself. It is the same with reflexive verbs. Verbs that tell the person on the receiving end to do something relating to themselves are reflexive verbs. They are used with the reflexive pronoun.
Wasch dir die Hände.
Waschen Sie sich die Hände.
Reflexive and Separable-Prefix verb Combination
You can also come across Separable-Prefix verbs that are used reflexively. Like here:
Schauen Sie sich im Spiegel an.
Hopefully this have helped you to make the Imperative mood a little more understandable.