Well there are a couple things, but I guess the primary thing is the lack of boiling. Since you're using primarily fruit juices, boiling will set the pectins in the juice, causing permanant haze (pectic enzyme can counter this, but I digress). To pasturize winemakers use campden tablets to kill off the baddies. Just make sure to wait at least 24 hours before pitching yeast after using campden, because the campden will kill your yeast too!
The second big difference is alcohol content. You're probably going to want to shoot for a minimum of 10 %, as your wine will need to age for a while, and the high abv will kill anything that might want to grow in there. Besides, who wants a weak wine?
The third is the aforementioned time. Give these things at least 6 months, or even a year to get good. I had a pom/blueberry wine I cooked up and it tasted simply like tart-alcoholic-juice at 3 months in the bottle, but once it hit 6 months it was like a commercial wine from the shelf, but still very unique. Still had some of that residual tartness though, so I'm waiting a few more months to see how it comes along. Don't give up on beermaking, its good to have something to do while waiting for all your wines to mature. Also poke around on these forums, there are a LOT of experianced winemakers, most of this info was gleaned from them.