Ok, so here's my advice Mr. Reece.. if you decide to accept it. [cue Mission Impossible theme song]
Sorry it took so long, not that its great advice or anything. Its probably boring, lame advice actually, but here goes it...
When I was a young lad and wanted to ask a girl out, I'd wait until I see some sort of sign from her that she might like me. If she smiles at me a lot and laughs at all my jokes then its pretty obvious to me that she might say yes to going out.. or if she seems shy around me but there's a lot of eye contact then I feel she'll say yes... but if she acts like I barely exist to her...then no.
The asking part is all about being casual, no pressure.. (in actuality, it really doesn't matter how u ask because the answer will be the same).. but to make it easier on myself I would make it sound like I'm already going to this place and was just asking if she wants to come along...
Example:
You: Have you tried that frozen yogurt place at the shops?
Her: Yes its very good,
or No I haven't.
You: I'm thinking of checking it out saturday. Would u like to come along?
Her: YES!!
or...
Her: No, because I can't have dairy.
You: Oh, so where's a good place to get non-dairy desserts?
Her: I like going to (name of place)
You: Maybe I'll check it out. Would you like to go there with me saturday?
..and BOOM! You are in like FLynn!