Do you or did you, which one is correct?

Could you please clarify for me which form of the verb "to do" is more appropriate in the context of asking about present or past actions? Is it "Do you" when inquiring about current habits or practices, or should I use "Did you" when asking about actions that have already taken place in the past? I'm trying to understand the nuances of these two phrases and how they differ in meaning and usage.