Object pronouns normally occur immediately before the verb. However, if the verb is an affirmative command, an infinitive, or a gerund (-ndo form), the object pronouns are attached to the end of the verb form. Note that when pronouns are appended to a verb a written accent mark is necessary when the stressed syllable is more than two syllables from the end of the word.

   No lo veo.                  - I don't see it.
  ¡No me digas nada!           - Don't say anything to me!
  ¡Háblenos usted!             - Talk to us!
   Favor de darme el libro.    - Please give me the book.
  —¿Qué estás haciendo?        - What are you doing?
  —Quitándome el suéter.       - Taking off my sweater.

If the verb form consists of a conjugated verb and either an infinitive or an -ndo form, the user has the option of placing the object pronouns before the conjugated verb or attaching them to the end of the unconjugated one.

Voy a verlo/Lo voy a ver.
I'm going to see him/you/it. (masculine)

Estamos buscándola/La estamos buscando.
We're looking for her/you/it. (feminine)