Get designs in the browser as soon as possible
The more responsive web work I have done, the more important I have found it to get designs up and running in a browser environment as soon as possible. If you are a designer as well as a developer, then that simplifies matters. As soon as you have enough of a feel, visually, for what you need, you can get it prototyped and develop the idea further in a browser environment.
If you are primarily a developer, then this can aid the design process hugely in order to get the design living and breathing in the browser. Without fail, every project that I work on gets revised in some way as a result of the designs being built in the browser. That isn't a failure of the original flat designs, it's a consequence of realizing that the design is just a step towards realizing an idea. And seeing it working in a browser is one step closer.
There is a slew of problems that can only be solved by seeing the design in a browser....
