[eluser]BrianDHall[/eluser]
As a general guideline I've found the best way for me is to first create a 'fake' application - a front-end that looks like the end product should look, at least with some degree of reason. Front-end first, in other words.
I've tried it the other way and it felt very frustrating. As much as Views are suppose to separate content from logic, I found that unavoidably certain front-end designs demanded changes in the code. I find it vastly easier to refactor a design than refactor or even re-write code, so I like decisions like "how the shopping cart looks" and "what the checkout flow should be" to be made before I actually have to code the logic for them.
My thinking is that you can't usability test or get meaningful customer/boss approval from backend code if they aren't coders themselves. So you end up 90% done with a project with no real way to find out how happy the customer is going to be. You might get down to the final details and its figured out "Oh, this checkout project takes too many steps, maybe it should be more like..." and now you just earned yourself an almost total rewrite of a half-dozen functions and refactoring of multiple views and controllers, or you try to hack out a solution that turns things into a big ugly mess.
I suppose most programmers just want to jump in and code, after all if you are a programmer you probably aren't a designer at heart, but I found that after the initial pleasure of setting up and starting a project fades the pain of wasted effort and rework makes it Soooo not worth it in the end.
So I find it best, so far, to go:
Discuss/think about what's wanted -> draw (pencil or on computer) paper prototype -> get a front-end design going, if not largely complete -> build 'fake' application, or "simulated prototype" (so you can click Login and it logs you in, for instance, but in reality it doesn't matter what you entered in the text boxes, etc) -> revise and rework -> once satisfactorily completely and most hidden issues uncovered, proceed with beginning of actual code and database design.
