* "Qué haces" is the informal way to ask this question, and it is used when speaking to friends or family. For example:
```
"¿Qué haces?"
"Estoy leyendo un libro."
```
* "Qué estás haciendo" is the formal way to ask this question, and it is used when speaking to strangers or people in positions of authority. For example:
```
"¿Qué está haciendo?"
"Estoy trabajando en un proyecto."
```
You can also use the phrases "qué haces tú" or "qué estás haciendo tú" to emphasize the subject of the question.
* "Qué haces tú" is used to ask someone what they are doing specifically, as opposed to what someone else is doing. For example:
```
"¿Qué haces tú?"
"Estoy estudiando para un examen."
```
* "Qué estás haciendo tú" is used to ask someone what they are doing right now, as opposed to what they were doing in the past or what they will do in the future. For example:
```
"¿Qué estás haciendo tú?"
"Estoy cocinando la cena."
```