Theory:

There are three ways of talking about the future in English, WILL, GOING TO and THE PRESENT CONTINUOUS.
For example:
I think I WILL eat fish tomorrow.
I am GOING TO eat fish tomorrow.
I am EATING fish with my sister tomorrow.

For each form, the interrogative form is constructed in a different way, and the same rules as those for the positive cases apply.

WILL - WILL YOU...?
So, let's start by looking at how to use WILL.
WILL is followed by the infinitive of the verb without TO, like I WILL CALL YOU.
It is used for situations where you are not 100% sure, when you say I THINK.
For example:
I THINK he WILL call. (You don't know for sure.)

The question form is constructed by changing the positions of the SUBJECT and WILL.
For example:
affirmative - YOU WILL call her.
interrogative - WILL YOU call her?

This example is also a prediction, but without any evidence.
So WILL is used if there is an element of doubt. (For a guess.)

GOING TO - ARE YOU GOING TO ...?
GOING TO is used when you are sure, or have some evidence to justify what you are saying, like when you have already made plans.
For example:
I am GOING TO speak to my boss. (You have made a definite decision.)
I know David is GOING TO be late. (He called to tell me).

The question form is constructed by changing the positions of the SUBJECT and the verb TO BE.
For example:
affirmative - YOU ARE GOING TO SPEAK TO YOUR BOSS.
interrogative - ARE YOU GOING TO SPEAK TO YOUR BOSS?
YOU is the subject and ARE is the verb to be.

PRESENT CONTINUOUS
Finally, using the present continuous for the future.
I AM SPEAKING ENGLISH NOW is the present continuous.
It can also be used for the future, for plans that you have made and written in your diary.
It is very similar to GOING TO, but is not used for guesses, so it is different from WILL.
For example:
I AM SEEING my dentist tomorrow. (I am sure because it is in my diary).

The question form is constructed by changing the positions of the SUBJECT and the verb TO BE.
For example:
affirmative - YOU ARE MEETING DAVID TOMORROW.
interrogative - ARE YOU MEETING DAVID TOMORROW?
YOU is the subject and ARE is the verb to be.