Chesco8691-san, eric-san,
kon'nichiwa
Thank you very much for the brilliant explanation, eric-san!
"Onegai shimasu" and "kudasai" can be both translated as "please" in English.
"Onegai shimasu" is used whenever you ask a favour to someone, while "kudasai" means more "please give me...."
This is the biggest difference between them, and that's also the reason why you can even use both in one situation, like
"...o kudasai. onegai shimasu" or "...te kudasai. onegai shimasu".
("Would you give me..., please? Thank you" or "would you please......? Thank you")
In some cases, "onegai shimasu" part can also be translated as "thank you" in English, but I doubt "kudasai" part could.
As to small and littel, eric-san's explanation is perfect
No need for me to add anything
Natsuko(奈津子),
Team JapanesePod101.com