The firs thing you should think about is the idea you would like to give: rustic, chic, country, eco, glamorous, traditional...and so on.
The element that should always be on a table are:
1. Proper Tablecloth
4.Cutlery & Glasses
Tablecloth: There are hundreds of colours and fabrics you could choose between: damask, silk, hemp, linen, cotton and mixed fabrics are just some of them. Decide to have not a tablecloth is a choice itself and should be in accordance with the idea you are giving.
Chair/Coverchair: an elegant and chic tablesetting always have coverchairs. Such as tablecloth, there are manycolours and fabric. Be sure the coverchair is well made and it covers the whole chair. If you do not like the shape or the fabric of the coverchair you should opt for a different chair that does not need coverchair. This solution is more expansive for sure but if you find the right chair, your table setting will change completely.
Underplate: Underplates gives the idea the table is complete. For sure, most of the time is a "plate" but an underplate could also be a napkin or a DIY round or even a leaf!
Centerpiece: Centerpieces would be an entire chapter to talk about. My raccommendation always are flowers. You could have whatever as a centerpiece but nothing is more "centerpiece" than a flower composition.
Cutlery & Glasses: this is easy if you trust the people who are going to set your table. They would know where to put cuttlery and glasses. A nice table should have 3 glasses: 1 for wine, 1 for water and the flute for the Spumante (or champagne). Silverware is not needed but the effect is great. Avoid coloured glasses especially for wine: you should always see the wine colour!