Use in Reflexive Verb
How would you know when to use reflexive and not to use reflexive verb?
ex. Si no acuerdas/ te acuerdas de la dirección, puedes buscarla en Internet.
ex2. Voy a quitar/quitarme los vasos de la mesa.
I just confused when it is appropriate to use it.
3 Answers
There are hundreds of reflexive verbs in Spanish-some of which are also reflexive in English. To wash yourself "lavarse" to seat yourself "sentarse" and many more.
Some that are not reflexive in English are "get" verbs in this language.
EX. enfermarse (to get sick) mejorarse (to get better ) casarse con (to get married) divorciarse de (to get divorced) Despertarse (to wake up) levantarse (to get up) and a bunch more of these.
It would be well to follow the link given by Jubilado and learn the lesson which covers a lot of territory.
The following is a very very short introduction to the subject.

You might want to read through this grammar lesson on this site:
I don't know if that answers your question here but this is a very big subject. One thing to remember is that "acordarse" means "remember" it's reflexive. If it is "acordar" it means "agree to". So in your first sentence you would only write "Si no te acuerdas la dirrección...." Recordar also means "remember" and is not reflexive.
Voy a quitarme los vasos would only be correct if they are on your body. Since they are on the table, you would say voy a quitar los vasos. Reflexive... the action affects you, voy a levantarme voy a sentarme