Of course we are called to holiness every day of our lives, but Sundays should be special, as we are celebrating the Lord’s Day. So my husband and I have tried over the last year to set Sundays apart from the rest of the week. We usually attend the Vigil Mass, so we celebrate the Sabbath from that point until Sunday night. We often will pick something up for dinner after Mass so that I don’t have to cook (a real treat for us, as this is the only time we “eat out”). My husband also makes us a special breakfast on Sunday mornings. We try to spend the day with family, at Adoration, talking with each other, praying, etc.
The Catechism has a description of how Sunday should be celebrated by the Catholic. It talks about service, rest, family time, etc.–you might look there for advice. God Bless!