I think for Chinese speakers, sometimes we would just directly say "请问你可以帮我吗?" because they'd be right in front of us. I have personally been addressed by people from mainland China as "姑娘", but it is extremely strange for usage outside mainland China.
Outside China, e.g. Taiwan/Singapore/Malaysia, "姑娘" is only used in China when dynasties were still in place. If you have local friends, remember to check with them :)