As apparently I'm the new ELITE I feel it's high time I wrote a bit about starting an alliance, and some general things you ought to keep in mind. I'll start by talking a bit about mindset, as that's really important.
First off, never do this unless you plan to enjoy yourself. This is a game. Games are meant to be enjoyed. If it becomes a chore, fark around until it's a game and fun again. The politics can be really grating, you'll learn to deal with it, it's better to know beforehand though.
Second off, standards. Never ever let someone into your alliance you, personally, do not like. If they cause trouble, get rid of them. You want to be surrounded by good, smart people. Don't accept anything less - I've been in alliances with hundreds of members, it's not worth it and not all it's made out to be.
Third, do not fark around when it comes to ideals. Just because you're a good little citizen of democracy in real life does not mean it's the best thing around for CN. Alliances exist as a means of collective protection, and little more. Anything that detracts from the ability of the alliance to maneuver and act in a timely fashion should be viewed with contempt. You're not here to make a perfect little democratic utopia, or 'hang about with friends' - you can do that any day of the week without having the same AA. You're here to do things by and for yourself, and if you want to be successful, you won't be setting up Congress's.
Fourth, do not have an elected leader. Just don't. This never ends well. Someone has to be the keeper of keys. All forums have a root admin - that needs to be the leader. All channels need someone to be registered to - that's your leader. When this is split up or "assumed" it will be passed on to the next guy who gets elected, stuff gets complicated and a good alliance can go down in flames. I've seen it happen.
Fifth, do not screw around with members who refuse to contribute. If they have grievances and refuse to suggest alternatives, or want everything their way, boot the mother. Your alliance is your army, do not mess around when it comes to discipline. Similarly, keep your ears open to good ideas. You'll have plenty coming your way with a good membership.
Six, peace is the time when alliances prepare for the next war. Nothing. More. It doesn't matter how small, insignificant, or unconnected you are. I started with no allies period - I was at war by the end of the week. You need to be constantly streamlining, constantly preparing.
Seven, think before you speak (in public). If you can't anticipate how people will react to something you say, DON'T SAY IT. You're representing more than just yourself, and you need to watch what you say. Big alliances have gone down because of incompetent leaders running off at the mouth and turning the public against them.
Eight, and probably one of the more important ones, get yourself some friends. Allies are important, but they aren't farkall if they're not friends. A friend should be someone you can say anything to, and not offend them. A friend should be someone you can scream to the high heavens in front of - kick and scream and cry bloody murder - and not be uncomfortable with it. You will be doing a lot of that sorta thing if you get into this game, and friends are invaluable.
Ninth, do not only sign up with big names. The best allies are the unknowns, not people everyone knows and has an opinion about. Shop around - find others who're starting out, pop over, say hi.
Tenth, record everything. When members sign up, record their ruler name so you can mass PM them. When you have official discussions with foreign diplomats, save the conversation. When you do aid deals with other alliances, screenshot it (Prnt Screen -> MS Paint -> Edit -> Paste -> Save As). Make sure you can prove everything and you'll never be caught flat footed.
Eleventh, do not take this game too seriously. It's easy to do. The analogy that most helps me is to think of this as a gigantic game of Pokemon. I wouldn't be bummed IRL if I lost a trainer battle - so too don't be bummed if you hit setbacks.
Twelve, and last, aid always. You should be borderline communist for at least your first three months. You aid up your members, they aid up the next guy, so on and so forth. Never stop. People have been building their nations since 2006 - you have a lot of catch up to do, keep that in mind.
That's about it. Hope it helps.