Well first off, it depends on what type of guild you want.
Being a guild leader can be simple, you can just have one for a group of friends. Do what you guys want to do and just have fun with the game.
You can also create a family guild, search out people in the game, make new friends, and play with each other.
Then there are also active guilds. I call them active, not because their online alot, but because they actively participate in inter guild activities, such as GvG and RvR. This type of guild requires a couple things:
~ Goals, not you're end game goals since there should never be such a thing, but you're general goal.
~ Time and dedication
~ Many great members that are helpful
~ A deep understanding of the game and guild system
~ A way to communicate outside of the game (optional)
~ Events, things to attract people and make it fun
And finally there are the hardcore guilds. I won't explain them, if you ever start a guild and end up hard core, you'll know it.
So it really depends on what type of guild you want to make. In any case, a good place to start is the sticky thread on this forum, here's a link: