ADVICE: Next time a girl asks you for the day of the date, reply "Whenever you are free". That will give her room to manuever and for you to chase up on it from time to time.
When asking a girl out to the movies it's good to nail the subject on the head. I.e. start talking about her favourite films and work your way to finding out what she is DYING to see at the moment. When the movie is mentioned make a point of how you as well have been DYING to see that film for a very long time and thus due to your equal burning interest in the movie, you simply MUST see it together to fully appreciate this work of art.
Both of the above when combined will make it extremely uncomfortable for the girl to weasel out of a movie date because:
1. No time/date was specified, therefore she would have to pretend she is busy for a very long time to avoid the date (And you can casually chase up on it)
2. She knows your interest and the fact that your plans are to see the film with her and not with anyone else (Due to similar interest)
3. It will make it very awkward for her watching her favourite film without you knowing your interest in watching this film with her (I.e. she will think that you are not watching this film because you are waiting for her)
I find it's good to never seem too obvious in the very beginning. It's good to start everything off with a simple friendship (Well at least the first couple of dates).
Well, I really don't want to turn this into a science, but hope above is useful
Don't cry, don't regret and don't blame
Weak find the whip, willing find freedom
Towards the sun, carry your name
In warm hands you are given
Ask the wind for the way
Uncertainty's gone, your path will unravel
Accept all as it is and do not blame
God or the Devil
~Born to Live - Mavrik~