First: Make sure you have decorations; there are tons of places to purchase these, such as partycity, etsy, oriental trading, etc. You can always make your own if you have the time.
Second: Give your guests the freedom to create their own delicious creation. Instead of going the traditional route (subs, hot wings, pizza), create a potato, hot dog, chili and/or pretzel bar.
We are opting for the hot dog and pretzel bar ourselves.
For the hot dog bar you can offer onions, mustard, ketchup, sauerkraut, chili, cheese, sour cream, relish, whatever.
For the pretzel bar we are giving our guests the option of both hot (homemade) pretzels and bags of pretzels that you would get from your local supermarket. They will be accompanied by different dipping sauces like chocolate, mustard, honey mustard, cheddar cheese, etc.
Third: You can't have a Super Bowl party without beer, so give your guests a selection of beers that reflect the two rival teams. Need some inspiration on which beers to get, then check out this article in Today Food.
Fourth: Organize some party games. One idea could be to have each guest predict the winner's final score and write it down on a tag that's tied to their drink. Whoever gets the closest to the correct score wins something fun like beer mugs or this Craft Beer Mug book.