I try to think in terms of interfaces, but implement quick & dirty. So, for example, I may imagine that data sources for a page will come from several places:

I try to think in terms of interfaces, but implement quick & dirty. So, for example, I may imagine that data sources for a page will come from several places: the db, Google maps, an api like Twitter etc. And I will create stub classes to capture this concept, but the methods will just return hard-coded elements. Eventually if the project goes anywhere I can build out the underlying methods as necessary. I find this helps me feel like I'm doing real engineering but not get too lost in the abstractions.