you say, "may i have that pretty please, with a cherry on top" :D

我需要它，你能给我吗？ when you say you need it ,I think he will give you

I only say:"hi give that to me thank you!".Usually I always get the thing I want.

i guess you can tell the one that how important the stuff you want means to you.

请给我xx好不好？(xx means the stuff you want) hope it helps