1) The custom is to eat specific foods on the night of Rosh Hashanah as a good sign. One does not eat foods which are sour or bitter on Rosh Hashanah. There is also a custom not to eat walnuts, as the word “Egoz” has the same numerical value as “Cheit” (meaning sin) when written without the “Aleph”. (Kitzur Shulchan Aruch 129)
2) At the table during the meals of Rosh Hashanah one should talk about words of Torah. Some have the custom to learn the Mishnayos of the tractate of Rosh Hashanah. (ibid)