Even though I never finished it (because of life), so I'm not a good spokesperson for it, I think the
Newbie Assignment is a great place to start.
Since it's your very first outing, I'd suggest removing the idea of asking out a girl in the mall from your head; that way it's not as stressful and not as much anxiety.
Approach 10 women with just very common questions and see if you decide to take it any further.
Examples:
"Hi, excuse me, do you have the time?"
"Hi, excuse me, do you know where the Starbucks is?" (or some other place)
"Hi, excuse me, do you know what time the mall closes?"
These should be pretty easy to ask. If you get the urge, then you can compliment them on their looks, but it's best not to worry about that the first time.
Some bonuses:
Go into a clothing store. If a girl asks if she can help you:
"Yes, but you have to answer honestly... Does this wheelchair make my butt look fat?"
This will get you a laugh from a pretty girl, so it should boost your confidence to keep approaching
Approach one girl and compliment her on what she is wearing or on her looks. Again, you are NOT asking her out, just brightening the day of a beautiful woman.
At a Coffee/Tea place, purchase something. When talking with the cashier, ask, "You look familiar. Do you got to school around here?" If she's in college, ask her major. If she's in high school, ask what college she is thinking about going to. If she's not in school, then say, "Oh, I guess don't know you then. Are you pursuing anything outside of here? Like beauty school or writing a novel?" This conversation may be awkward, but it's just giving you experience/practice with conversation, so again, don't stress about it. If it goes poorly, who cares.
Good luck!