1. IRREGULAR SINGULAR AND FORMAL PLURAL COMMANDS
INFINITVE
USTED COMMAND
USTEDES COMMAND
Dar
Dé Ud.
Den Uds.
Estar
Esté Ud.
Estén Ir
Vaya Ud.
Vayan
Saber
Sepa Ud.
Sepan
Ser
Sea Ud.
Sean
Attach object and reflexive pronouns to the end of the affirmative formal commands. In order to keep the original stress of the verb you may have to add an accent mark.

2. NOSOTROS COMMANDS Hablar Hablo Hablemos Comer Como Comamos Escribir
To suggest that others should do an activity with you, you could use the nosotros commands.
To form the nosotros command, substitute the –o of the present-tense yo form of a verb with –emos for most –ar verbs, or –amos for –er/-ir verbs.
Keep the original stem when conjugating the verb to a nosotros command
INFINITIVE
YO FORM
NOSOTROS COMMAND
Hablar
Hablo
Hablemos
Comer
Como
Comamos
Escribir
Escribo
Escribamos
Cerrar (ie)
Cierro
Cerremos
Volver (ue)
Vuelvo
Volvamos
Divertir (ie, i)
Divierto
divirtamos

3. NOSOTROS COMMANDS CONTINUED
Object and reflexive pronouns that follow and are attached to affirmative nosotros/as commands.
Although, when combining a direct object pronoun with the indirect object pronoun se,and for reflexive verbs, drop the final consonant –s before attaching the pronouns.

4. SABER AND CONOCER
As you have probably already learned, ser and estar are used in several different situations as “to be.” Saber and conocer are used in the same way for “to know.”
Saber is used when you talk about facts that someone may know or not know.
When saber is followed by an infinitive, it indicates that someone knows how to do something.
Conocer is used when you want to discuss whether or not someone is familiar with people, places, or things.
When you use conocer to refer to people, be sure to add the personal a after the conjugated form of conocer.

5. SABER sé
sabemos
Sabes
Sabéis
Sabe
saben

6. CONOCER
Conozco
Conocemos
Conoces
conocéis
Conoce
conocen

7. NEGATIVE COMMANDS
To make an affirmative command negative, just add a “no” before the verb.
Ir has one exception for the nosotros/as form: ¡Vamos  ¡No vayamos¡
Maneje Ud.  No maneje Ud.
Duerman Uds. No duerman Uds.

8. NEGATIVE COMMANDS CONTINUED
The negative tú command also has an exception. The negative tú command is formed by adding an –s to the end of Ud. and add “no” before the verb.
When adding an object/reflexive pronouns it must go before the verb instead of going after the verb.