Pronouns and the RID rule

 RID  order                  
when you have two object pronouns in a sentence, these pronouns always appear in the RID order. And because two is the maximum number of pronouns that can appear together, the possible combinations are

RD – reflexive – direct
me lo compro  - I buy it for myself
¿Tu pelo es magnifico. te lo lavas mucho?

ID – indirect – direct
Yo te la escribo - I write it to you
Ella me las vende – she sells them to me

La La Rule       
When both the direct and indirect objects are in the third person, regardless of gender and number, both pronouns will begin with 'L'; so change the indirect object (the first one) to “se”.
consider the sentence - “I give it to him” - this would become
“Yo le lo doy”, so we change this to “Yo se lo doy”.
negation(1 verb)  put the no or the negation word before first pronoun.
When sentence has 2 verbs, there are 2 options
Quiero dartelo
te lo quiero dar
negation (2 verbs)
no quiero dartelo
no te lo quiero dar.

=============================================================

Direct Object Pronouns       

what does John have?  (What)
whom does John see? (Whom)
me, te, lo/la, nos, os, los/las

He has the book             the book = direct object           
John sees Mary (her)      mary = direct object

John lo tiene                   lo = direct object
John la ve                       la = direct object

Negation (with one verb)
Yo      no       lo      sé
         nunca   lo      estudiáis
            |          |        |
     neg word    |        |_ conjugated verb
                       |
                 direct object

Two verbs then two options
1)  te                    quiero                        ver    
      |                         |                              |
  direct object   conjugated verb        infinitive

2)  quiero                    verte
        |                            |
  conjugated verb        infinitive+direct object     
                              
Negation with two verbs
1) no                           lo           tengo que         leer
 negation word   direct object   conj verb      infinitive

2) no tengo que leerlo

=============================================================

Indirect Object Pronouns         
To Whom (or) For Whom
me, te, le, nos, os, se
            |                  |______(them, you)
            |_ (him, her, you, it)

DO = direct object     IO = indirect object





He buys me flowers (he buys flowers for me)
                                                   |_DO     |_IO
In a sentence with an indirect object there is always a direct object either stated or implied.
           My Gradmother writes me every week
                                         |      |
she writes(DO) something_|      |_ to me (IO)
           
the direct object is understood to be a letter, postcard, or note
with one verb, IO before conjugated verb
Juan me compra un libro

With two verbs there are two options
1) before the first conjugated verb
    él me quiere dar un regalo
2) on the end of the infinitive of the second verb
    él quiere darme un regalo

Negation
1) after negation and before verb
    él no me trae nada
2) on the end of the infinitive of second verb
   él nunca quiere traerme nada
============================================================= 

Reflexive Object Pronouns                  
me (myself)
te (yourself)
se (himself / herself / itself)
nos (ourselves)

os (yourselves)
se (themselves)

The action of the verb is to self

me lavo el pelo cada dia
I wash  my hair every day
Nearly all verbs can be made reflexive, there is no magic trick !  If the action is to self then it is reflective.

Preposition + Infinitive with Reflexive Pronouns
verbs following a preposition must be in the infinitive, with reflexive verbs the infinitive remains untouched and  the reflexive pronoun is added to the end of the infinitive to agree with the understood subject

Yo leo antes de acostarme
                  |              |     |__(reflexive pronoun on the end of the verb)
          preposition      |
                              infinitive

                                             infinitive
                                                   |
antes de dormirte, tú necesitas lavarte
       |            |     |                              |
       |            |     |_______________|__(reflexive pronoun)
preposition   |
                infinitive