I started with a big spreadsheet, something like the pig calculator you can download from here but with a separate sheet for each of the parts of our farm, e.g. veg, pigs, eggs, christmas geee etc. This worked really well to help us nail down what we had to achieve in order to get the farm running properly. Where I didn't have figures I think I asked on here! Although mainly we were doing what we'd done before in a back-garden scaled up to a smallholding.
The main downside was that I didn't really pay much attention to the path to that goal. Its taken us four years to get to the stage where the farm can pay me regularly and I think it could have gone a bit more smoothly if we'd had a clearer plan for how to get there.
e.g. the christmas geese and turkeys do really well for us and have very little capital outlay so I should have started them sooner. Same for our hatching in schools - makes good money for little effort and a capital investment of a couple hundred quid for an incubator and brooder - its also a good way to get your name known locally.
Finally, we went for breeding sows too early - should have built up more experience and a bigger market for the meat beforehand as they are very expensive to keep.