I would suggest Ian Dunbar's website
http://www.dogstardaily.com for the best advice on all aspects of dog rearing and training. Lots of good advice using positive training methods.
Lots of dog trainers use the principle "nothing in life is free" so your dog starts to "work" for his food by sitting, coming when called etc, and sits for you to open the door to go outside, come inside. So instead of allowing your dog to free feed, you keep a large proportion of the dog's meal handy out of dog's reach, and use it throughout the day to train your dog.
Be cautious of the amount of food recommended on dog food packets -- often they are greatly exaggerated (sell more food that way!) and it is very hard to get weight off (as we all know). With a large breed dog you need to be careful of bloat, caused by overeating, exercise after meals, drinking too much water after a large amount of dry food etc, so make sure you read up about this.
I especially agree with using Kongs for chew toys -- there is a Kong web site with ideas about filling the Kong.
cheers
Sandra