If you're happy with English knitting (have a good yarn hold, things are going well), then it's probably not worth trying continental/German style. It's just a different way of doing the basic stitches - you hold the yarn in your left hand, and pick it up with the right needle, rather than holding the yarn in your right hand, and throwing it around the needle.
German-style is better for: circular knitting. Knitting is easier, but purling is, in theory, harder. I find German-style better for everything.
I find it totally easy to make up my own patterns. Once you know the basic shape of a garment, changing it a bit, or adding a pattern or texture, is really easy, particularly if you're ok at arithmetic. But I only really do flat simple things, and hats. I expect sweaters to be harder - tamum has made her own sweaters.
It's also much harder to write out a pattern, properly. I wrote out one of my hats (the butterfly one) for someone from MN, and rather than a nice tidy "do this, do this, do this" pattern, it was a long discursive letter on how to work it with whatever yarn you had etc. But then, I'd rather have the idea of a hat, than specific instructions for a specific yarn, as I always buy yarn first then figure out what I want to do with it. So I always have to adapt etc.