I found the learning to play process fairly simple. I actually haven't bought a single seed yet. I grew the "starter seeds" that were already in my inventory and had those self-pollinate so that I had a stock of seeds. Then I played around with cross-pollinating a little to get some new seeds. Once I found my magic plant, I worked on growing and selling as many of those as possible (while using them to produce more seeds to make more of them) until I had enough cash for the best soil.

Now I'm back to cross-pollinating to see what else I can find. I have to start getting serious about my charting though since only the "first generation" seeds tell you their parent plants.