Firstly, grab your mobile phone. Send out a short text for invitation. If you want something more fancy, then maybe you could make some invitation cards, but I wouldn't encourage this as you will be using paper and how are we supposed to save trees if we did that? Another option would be emails, which might not be as convenient for most people.
Then, plan with a budget because over-spending over the New Year isn't the best way to start it. This solely depends on the amount of people that are invited. So don't under or over budget for the party. After you have done that, set a suitable menu for the party. Will there be finger-food or a proper dinner? Make sure you take note of the allergies of the people that you have invited. I'm pretty sure that you wouldn't want to ruin the party with any sort of unfortunate events. After that, it's time for the shopping. Go get the groceries and decorations within the budget that you planned earlier.
Besides that, make sure that you have a good plan of activities during the party. Get a nice playlist of song suitable for the party. Plan games to keep everyone enjoying the party. If there are kids, make sure that they are well occupied while the older ones have an amazing time.
Don't forget the countdown.
Well, honestly all of this is very materialistic. You don't really need to spend money for a perfect New Year celebration. I am saying that because I'm going to snuggle in my couch with my mum on the eve and countdown to New Year with her without a party and I can already say that it is going to be amazing as it is going to be a beautiful 2015 even without a lot of people around.
But I hope those who will be celebrating on the Eve of New Year have a blissful time. Make sure you don't drink and drive and be safe!
HAPPY NEW YEAR!