If you had a party and served frozen foods, beer in cans, wine out of a box, no music at all, and kept the light on, the party would not be too great at all. There are rules for entertaining good food, good drinks, and atmosphere.
Casual parties should even serve fresh, good food. Finger foods are the best because there are no utensils that are needed so there would be less of a clean up afterwards. Serve the finger foods on a tray so you don't need to run back and fourth from the kitchen. You too need to have enjoyment from the party.
Remember to never serve beer in cans. Wine should be bought in bottles. There are still great deals even though it is not from a box. It is always a good idea to have some liquor in the house anyway, just in case you have guests drop by that like to have a drink or two.
The atmosphere is made up of three main things; music, lighting, and decoration. There needs to be music at every party. Where there is good music there usually is dancing, and parties are a lot better if there is dancing. With the lights on nobody will even think about dancing. It is a good idea to have your light switches changed to dimmer switches sometime if you plan to have a few parties over the years.
The table with the finger foods and the liquor will probably be the focal point so pretty it up with some flowers and a table cloth. If it is a theme party you are having then you need to decorate accordingly. There is no need for anything tacky, just flowing decorations.