When I start a new project, I often times immediately start thinking about the details of implementation. "Where am I gonna put the DataBaseHandler? How should I use it? Should classes that want to use it extend from some Abstract superclass..? Should I use an interface? What level of abstraction am I going to use in my class that contains methods for sending requests and parsing data?"
I end up stalling for a long time because I want to code for extensibility and reusability. But I feel it almost impossible to get past thinking about how to implement perfectly.
And then, if I try to just say "screw it, just get it done!", I hit a brick wall pretty quickly because my code isn't organized, I mixed levels of abstractions, etc.
What are some techniques/methods you have for launching into a new project while also setting up a logical/modular structure that will scale well?
-- EDIT --
Well, this is already the type of question that is difficult to accept an answer to, but wanted to get some more feedback, see if there's some consensus. TDD sounds really cool and, frankly, I've been meaning to get more up to speed on using JUnit, etc. At the same time, what do the fans of TDD think about the fact that one legitimate point with relation to TDD solving my particular issues, is that TDD doesn't really seem to address the question of design. Sure, I agree TDD will help me define what I want to do and then I can gradually work through the how, but there are many different overall design patterns/structures that could all pass through unit testing. That's just it: it tests single UNITS. I guess I'm a bit confused... I dunno. Maybe I'm just trying to procrastinate even more by trying to figure out some magical formula, but I would like to hear how some of the veterans approach this area...