A good idea for starting a new character is to work with basic shapes. To be as simple as can be. This goes too for the ideas about the character. I mean this is not the moment to pull out a twenty thousands page document about the character. Because it is more than likely that all that information will either overwhelm you or make you overprotective of your 'baby'. So it is better to start with the most simple ideas and most basic of shapes.
Talking about that, the basic shapes are the triangle, the square and the circle. Perhaps you have noticed or perhaps you haven't, but character are form by one, two or all three of these shapes. This doesn't mean that the characters, for the most part, look like bulky things. The characters hold the shapes in their overall figure, or even some shapes within.
Why are there basic shapes hidden within the characters? And even more important how working with said shapes while designing a character helps you? Well, the easiest way to answer both questions is that the shapes can create an instinctive association for someone. Let's call it a gut instinct. Because of that it is easy to associate the shapes with some ideas and characteristics. These helps to inform certain aspects of the character without the need of any exposition or dialogue.
Easy to read characters are form with one shape. This works better for characters meant for children or for something that is meant to be quick and easy to read like a comic strip. Then you have those characters that are less simple and one dimensional. Those have a combination of the shapes. That way different aspects of the character can be conveyed visually in a way that is quite simple to understand. And that can give and idea about the character that goes beyond the most basic stuff.
This will continue on other posts.