Answer:
-Can I help you, Sir?
-I would like a leather jacket, please. Black or brown.
-We have this one, Sir. Do you want to try?
-What size is it?
-Uh... 46 size, Sir. Is it ok?
-No, it's too tight. Do you have something larger (or taller)?
-Ah, no, Sir. I regret, that's all we have for leather jackets.
-That's a shame... But I like this mackintosh (or raincoat).
-Which one, sir? This one?
-Yes, this one. Can I try it, please?
-Sure, sir. The fitting room are in the end at the right.
-That's ok, I can try it here.
-It goes really well on you, sir.
-Yes, but it's a bit to short. I would prefer a longer mac (or raincoat).
-Good morning, I would like a pair of gloves, please.
--Yes, madam(or ma'am), we have this one in wool, if you want.
-I like the black ones. I can I try them, please?
-Sure, madam. Here they are.
-Ah, they're a bit to small. Do you have something larger (or bigger).
-Yes, here is a larger (or bigger) pair. Does it fit? (or does it go well?; or is it okay?)
-Ah, yes, it's perfect. I take it.
-Do you take this belt too, madam?
-No, thanks, it's a bit to expensive for me. In any case, I would prefer a different colour (or color). Do you have white or grey belts, please?
-Wait a moment, please. I'll check it.
Don't hesitate to correct some mistakes because, I'm French and not English. I hope you enjoying your french courses. Good luck!