First crocheting a piece for person other than myself

[nala]

Hey, so my customer gave me their measurements bust etc. how do I make sure it's not small or too big. Like around the legs.

 

[Granny Square]

It sounds a bit risky to make a custom fit garment long distance, without personally measuring them. People have atypical waist lengths*, a not proportional top & bottom, all sorts of possibly unexpected things could pop up...

I would ask your customer to measure the areas you forgot to ask her for earlier- and then use that number and add the amount of ease appropriate for the garment type in that body area for the stretchiness (or not) of the fabric you're making.  

*if this is something where 'bust' and 'legs' fit into the same garment, this measurement is critical. I have a short waist length, used to sew a lot of my own clothes for working in an office and had to make adjustments if something went past the waist that was fitted, like a dart for example, or add length above the waist for a peplum style.  Here is a link that explains it