Is this polite expression?
I have a question. When you have a favor from someone, then will you use
"You want to〜？"

For example, if I want to go to the station, then If I ask to my partner→
"You want to drive me to the station?"
Is that good? Polite? Normal?

"You want to" is acceptable but I would use it for people you know than strangers. For strangers, more polite "Could you drive me to the station? please." or "Could you, please, drive me to the station?" Using "could" gives the sense that the reciever can either "Accept" or "Deny" the request. Note: even with close friends, you can use "could" to ask your request if you feel that the person may or may not be comfortable with the request. Because, "could" doesn't sound demanding. This applies to "would" too, see below:

But, if you want to imply that you want someone to do something with a less chance of denying, use "would" , "Would you drive me to the station? please" . Summary: "could" = "can", "would" = "will".

Example,

A guy asking out a girl: "Would you like to go out sometime for dinner? lets say this weekend at 8?"

The girl can answer either "yes" or "no" but, using "would" implies that he want's the girl to say yes. (though, some guys could say "Let's go out to dinner this weekend? like around 8?" this sentence is more direct but it shows off the guys confidence.)

I thought that if I have a favor from someone, then I should use "Can you〜？"
You can use "Can you" but I would use it for people you know. Not strangers, because it can come across as being demanding which becomes rude.

I thought that's more polite. But it will be too direct? It's ok to be direct with people you know. If it's a stranger it can come accross as rude.
If I ask "you want to〜？"then it will be more kind to other people? Because I can give them more options? ?

When I hear that "You want to〜？"
I thought that "No No No. Why I want to?! YOU want to, right?" Lol

Examples of using "You want to~?"

Context: Studyin' for exam.

A: Hey, how's math?

B: Brutal... /sigh

A: Ya i know what you mean...

B: ya , and next week we have a midterm

A:bah, ya...You wanna study this weekend together?

B: yea, sure... at the library at 8am?

A: sounds good!

Example 2:

Context:Partyin at a bar. A & B, both think Karaoke is silly. or A knows that B doesn't like karaoke and is teasing him or her.

A: hey you wanna go try that karaoke?

B:nahhh!!

A: I know YOU want tooo!

B: lol,nahhh I'll pass.

A: lol

Note: conversations are between friends

I don't know if I could explain what I want to say.....

I hope this extra info helps :)

Yours is a question, not an entry, so there's no correction involved.  Asking favors is usually done with conditional sentences.  Could you and would you are most common:  could you give me a ride to the station, would you give me a ride.  May is formal English:  may I have a ride?  Asking if the person wants to give you a ride is completely different  Would you like to give me a ride is a good way to express it and much less direct and much more polite than demanding to know if the person wants to give you a ride, which is what you are doing when you say 'do you want to'.

Send me a message and contact me if you want me to send you the grammar book with the information about conditional sentences.  My Skype:  brian.madden4 

Good luck to you!

Is this polite expression?

I have a question. When you have a favor from someone, then will you use
"You want to〜？" This depends.  If you are very close friends, this is acceptable.  However, it is better to say, "Could you PLEASE..."  This is always polite.   You can also say, "If you don't mind, it would be great if you can...."; "I am wondering if it is possible for you to...."  Always include a "please" and a "thank you". 

For example, if I want to go to the station, then If I ask to my partner→
"You want to drive me to the station?"
Is that good? Polite? Normal?

I thought that if I have a favor from someone, then I should use "Can you〜？"
I thought that's more polite. But it will be too direct?
If I ask "you want to〜？"then it will be more kind to other people? Because I can give them more options? ?

When I hear that "You want to〜？"
I thought that "No No No. Why I want to?! YOU want to, right?" Lol

I don't know if I could explain what I want to say.....