Use acrylic latex primers and paints when the table is painted. They provide a protective finish that is resistant to scratching.
Measure the tabletop dimensions with a tape measure and get a tempered glass or Plexiglas tabletop covering. They can be found at furniture or hardware stores and can be cut to your specifications. Since the covers are clear, they allow the tabletop to still be seen without obstruction while providing protection against scratching or impact.
Position cloth place mats around the table on areas that get used the most. They can be decorative and protect the table at the same time. Cloth is better than vinyl, which can stick to wood and cause damage over time. Either one works well if a glass top is already in place.
Consider the use of a tablecloth. Tablecloths can be very beneficial during family dinners or other occasions where the table is experiencing high-usage and there is a high probability of spills. The tablecloth can prevent stains from affecting the table and then it can removed and washed later.