In order for a party to be successful, you need to do quite a bit of planning in advance. Not only will this ensure everything is taken cared of, it will also make you, the host, more relaxed when the party is in full swing, knowing that you have checked everything off.
First of all, go over everything you will need and make several lists. Plan out the food in details with shopping lists and time tables. Are you renting glasses and plates, otherwise make sure you have enough. What about the bar, what's the plan there? It's a good idea to go over everything you're serving and what you're serving them on.
Next, think about when the guest enters, where do they go? Is there someplace to hang the coats and what about muddy boots and wet umbrellas?
Atmosphere is a big part, so carefully think about what kind of music you want to play as well as the lighting. Candlelight is great here, it increases the atmosphere, plus you can't see if everything is in top shape in your home!
When it comes to the food, it's usually better to make things simpler as opposed to more advanced. After all, you don't want to be worrying about the food as the guests start to enter. It's a good idea to focus on food that you can serve in room temperature such as thinly sliced cooked meat, quiche, cheeses etc... Of course a big pot of hot soup or stew is also very nice and simple to manage along with some good bread.