We would like to make a Day trip to Hong Kong from Macau.

You can easily take a ferry from Maritime Ferry Terminal to HK and the ferries may arrive at HK-Macao Ferry Terminal or China Ferry Terminal. For the schedule, you can check on Turbojet.

About the sightseeing, you can go to Ocean Park, Causeway Bay and Victoria Bay. To be honest, one day is too tight to tour around these scenic spots. You'd better start from Macau early.