Just take it easy as you're getting used to the car, especially if the weather is bad, this advice would go for any car regardless of how the wheels are powered.
Don't drive like an idiot and it won't make a difference whether the car is RWD/FWD/AWD
The biggest risk, in my opinion, of driving a new car (especially me coming from a Vectra), is the sheer array of buttons at hand. I'd spend some time parked up at the dealers getting to know where everything is; hazards, demister, radio/phone buttons etc. Last thing you want to be doing is messing with buttons doing 70mph on a motorway home.