Hi Azul,
Here's what helped me. I decided to design a new cartoon character for a company I worked for. I was their graphic designer and I ended up doing a ton of illustration work there.
The idea was to create a cartoon character that matched the business environment. I started by thinking a lot about what "aura" the company and its employees gave off. I know you probably aren't doing this for a company to use, but I think it may help to read someone else's general process:
1. Type of company: Direct sales of printing equipment
2. Type of management: Persistent, ex-Marine Corps hardcore-sales guys
3. Type of books the company members would probably read: Old self-improvement books like "How to Win Friends and Influence People" and other motivational (if corny) sales materials
4. Age of salesmen: 30-60
This got me thinking about the type of cartoon character that would really resonate with these guys. I started to imagine this slick salesman with big elvis hair and a skinny tie. I thought about the movie "Big Fish," especially the part where the main character is a salesman. Honest, hard working, knows how to extract money from people, and prone to make dumb mistakes here and there.
So, I decided to make him pretty fragile and skinny. Overall:
1. Hair: Big, a sign of confidence and optimism
2. Face: Handsome, or else he wouldn't be in sales (that's what all these guys think) - thin nose, sharp jaw, bushy eyebrows, small ears
3. Clothes: Black (slightly warped) tie, black pants, black pointy shoes (this company had *no* color at all, believe me, and these guys are used to reading Zig Ziglar books with black and white cartoons

)
4. Line quality: Very sharp, sharp corners everywhere - his whole persona is "sharp."
At this point, I had something. I opened up Illustrator and within about two hours I had him down. I knew he would work when the sales guys peering over my cubicle wall started laughing and asking who he was. The character ended up being a big hit, especially with management (where it counts, he he)
To sum up, this creation was a caricature of the whole company. I don't mean that in an abusive way, but in a "wow, how true" way. The cartoon character really resonated with people there. In my opinion, if you start out by analyzing your target audience, really getting into their minds, you will come out with gold and the drawing will create itself (said by a guy who practices a lot...caveat emptor

).
If you are just creating a new character for the heck of it, try to give yourself something interesting to work with. I started a comic about myself once (albeit myself in an alternate dimension) and found it really hard to be excited about, after a point.