Almost everyone has at least some experience with Nerf or other off-brand products. Whether you own your own blaster or just have a friend that does, chances are you've played with a Nerf product at some point in your life.
Stock and even slightly modified-class Nerf wars are very low range events; in general no blaster will exceed 50 feet in range. Nerf Internet Community or NIC wars, however, are very different in how they play out; they are more similar to airsoft than they are to a stock class war. As such, there are a few things to consider before you attend your first NIC war.
First, you need to have at least two different blasters; one primary and one pistol. A primary can be any blaster at all and a pistol is usually a small, single-shot, spring powered-blaster. Primaries can be anything, but as a general rule you want to aim to hit 100 feet or the century mark. Rules for pistols vary greatly depending on the host, so make sure you read up on the rules for the event you plan to attend.
You will also need darts and even modified stock darts are generally very poor substitutes. You might want to consider purchasing darts from a respected member of the community, as stephans take a lot of practice. If you purchase darts from someone who isn't local, make sure that the darts conform with the war host's regulations.
Making a primary can be anywhere from a simple to an incredibly complex task, however there are a variety of guides on the internet which can make the task much easier. There are a few common rules to for you to keep in mind:
Range is the most important feature at least up until about 100 feet. Most wars will ban things that shoot more than 140 feet and several wars cap ranges even lower than that. Ranges are always measured by how far a blaster shoots when the barrel is parallel to the ground.
Rate of Fire or RoF becomes increasingly important once the blaster shoots at least 100 feet. A reasonable RoF would be about one dart fired every three seconds.
More ammo capacity is almost always better; as long as it doesn't become too bulky.
Make sure you read up on all the rules and as many gametypes as possible. If you don't understand a gametype, ask questions about it. It's better to ask a lot of questions and know the rules than to not ask questions and break rules.
Don't show up to your first war assuming that you will be one of the best players on the field; chances are that you'll be lucky to fall in the middle of the pack. Don't get discouraged; you'll do better at every war you attend. If you work on improving yourself and your blasters for each war, you'll quickly become a competitive player.