Recently on vacation I wanted to ask a Chinese tourist if they would mind taking a photo of my wife and I - but I didn't know how, so just asked
你可以吗? (nǐ kěyǐ ma?) while pointing to my camera.
How should I ask this in future?
There are many ways to ask this. Some examples:
照张相 means to take a picture, so does 拍照（片）。 You can both use 能 and 可以. 帮（助） means to help. 我们俩 means the two of us. 给 is here a proposition.