Character creation is a three-step process, starting with the concept, moving on to Power and Aspects, and finally Skills. Use the Sheet Template as a guide to building your character sheet.
Concept
The concept is the most important step. Here's where you decide just what sort of person you want to play. Concepts can range from a hacker who ran across a .pdf book of shadows to the last scion of a forgotten pantheon of gods, with only a shadow of the divine power. The Serpent's Hand takes in all types. The one common theme that all members share is that they're on the fringes of the normal world and the paranormal. You still operate to some extent in the everyday world, even if it's just to the extent of taking a walk on the streets every now and again to remind yourself you're still human. However, you know things that the majority of humanity simply couldn't know. You've walked the hidden Ways. You've met creatures that people wouldn't even imagine exist. You can do things that no one else can do, or at least know someone who can.
So, first think about how your character became involved in the weird and the strange. Do you have supernatural abilities? Is your entire family aware of the paranormal? Or did you just happen to stumble across something weird? This is likely to be central to your character's concept, as it's going to color how they interact with the rest of the world.
Next, think about how and why they joined the Serpent's Hand. Are they devoted to the cause of sharing knowledge? Maybe they view the struggle of supernatural entities as a new Civil Rights movement. Or maybe they're just trying to survive in a world where being able to make your hair turn green on command can get you killed. There's strength in numbers, after all.
Finally, think about their history beyond their ties to the supernatural and the Hand. Do they have a day job? What did they do before they learned to cast spells? What sort of people do they know on the outside?
You don't need a lot of detail here, just enough to know what sort of person you're putting together. You can figure a lot of this out on the fly later on.
Example
Jack's decided he wants to play someone with the ability to hear voices, which impart advice and information he couldn't get elsewhere. For a name, Jack decides to go with Billy Schitz (for schizophrenic). It's a bit silly, but it's memorable. It's probably not Billy's real name, but there are plenty of reasons he might protect his real name. The voices led him to the paranormal world, where he discovered there were others like him. After a run-in from the GOC, he fled to the Library, and joined the Hand.
Now, to make things interesting, Jack decides that Billy is an actual schizophrenic. He has to take medication to only hear the real voices. He's still high functioning, but he tends to be a bit twitchy. He doesn't talk to his family much these days (no one wants to talk to the crazy guy). Despite all this, he's managed to make a healthy sum from the stock market (though never enough to draw attention to himself. He lives comfortably, and it lets him spend most of his time at the Library. It's a haven for him, a place where he doesn't have to hide who he is.
There's certainly more to his story than this, but for now, we'll keep going with character creation.
Power and Aspects
Now, odds are you already have a pretty clear idea of what your character's Power is. The question is how to model it mechanically. Take a look at the Powers listed in the Powers and Aspects page and try and get it into the ballpark from there. Talk with a GM if you get stuck. In general, good powers either add a nice bonus or give a new use to a skill (or grant the use of a new skill entirely, in the case of Magic).
Now, once you have your Power, try and come up with three Aspects. These are phrases that describe important themes about your character. They can be personality traits, signature equipment, or people they know. They should be things you think are going to come up fairly often. Try to come up with a nice balance between useful and troublesome.
Example
Billy's power is hearing voices that offer real, pertinent information. Jack decides that this should give a bonus to Lore. However, he also likes the idea that sometimes the voices tell him what other people are up to, so sense motive might work too. At this point, he could simply reflavor the Badass Normal skill as being paranormal. However, he wants something a little different. So, he lowers the bonus from two dice to one, and then gains the additional ability to use Lore to find out about mundane people as well as supernatural creatures. Either use costs a Fate Point.
Finally, Jack and the GM decide that the voices can sometimes tell him random information that's useful to the plot. This feels like it's making the Power a bit, well, overpowered, but this is really a tool of the GM, not the player. The GM can use it to feed Billy as much or as little information as he wants.
For Aspects, Billy first takes On Crazy Pills. He has to take his medication to function, and there are sometimes side-effects. This is mostly a negative Aspect, but it's good for generating Fate Points. Next, he considers taking Newbie Greeter. He reasons that the Billy spends most of his time in the Library, and knows most of the new kids there. The GM likes the idea, but cautions that it would be difficult to use when not dealing with Serpent's Hand members (against whom he's not likely to roll). Instead, Billy takes GOC's Most Wanted. The GOC knows his face, and he has to keep a low profile to keep them off his back. However, it also gives him extra determination and know-how when dealing with paragovernmental organizations. Finally, he takes Let My People Go. He's dedicated to helping others with supernatural powers live in peace, without having to worry about organizations like the GOC or the Foundation going after them.
Skills
Skills represent what your character is good at. Everything that you need to roll is based off of your skills, which are found on the Skills List. If it doesn't happen automatically, it's based on skill. Each character starts off with nineteen skill points to distribute, with up to four points in any given skill. Try and get four points into at least one or two skills that represent your character's main specialty. Remember that you get one point of Lore and two points of each Health stat for free.
Example
Jack decides, first of all, to up Billy's Lore to 4. Billy's main schtick is that he knows things, so it makes sense. He adds 2 points into Perception. Billy keeps his eyes open, but he can be fooled (though the Voices can sometimes help with that). Billy needs some sort of specialty. Jack decides to give him 4 points into Sneak. Billy's no thief, but he uses a lot of the same skills to sneak in and out of places. Finally, he needs some good combat skills. Jack gives him 2 points in melee, and raises Body and physical defense to 3 and mental defense to 2. Billy knows a bit of self-defense, but he'd prefer to cut and run if at all possible.
Now Jack's finished with character creation. But there's still a lot of questions left unanswered. Where do the voices come from? How did he encounter the GOC? What are his plans? Jack hasn't figured those out yet, but they can be explored in-character. Now it's time to drop Billy into the game and see what happens.