The first step would be to lightly sand the table to remove any type of coating or varnish. If there is a coating or varnish other than paint, the labels will peel up. Next Mod podge :http://www.plaidonline.com/mod-podge/brand/home.htm the back of the wine labels, place them on the table and then use a layer of Mod podge over the labels. The Mod podge will usually dry clear, but if too heavy you may get some white spots. If this happens then lightly sand with fine sand paper and it will come off. Allow it to dry well. When dry you can spray the whole table with a Mod podge sealer.
The more layers of sealer you apply, will make the labels look as if they were painted on rather than decoupaged. If you want a shiny finish, you can use furniture wax like Min wax. The more you rub the shinier it will get.
Please let me know if you have further questions and I will be happy to assist you. My goal is 100% Excellent Service. Joan