Asking questions like this can help you to identify the pieces of a model. Once you've got a pretty good idea of what the pieces look like, you can move on to the next stage. Most students think that the next stage is to prove a theorem or run a regression. No! The next stage is to work an example. Take the simplest example|one period, 2 goods, 2 people, linear utility|whatever it takes to get to something simple enough to see what is going on.