on C&C games you've gotta do a few things:
1. Build loads of ore trucks (or equilavent money making thingys) and always have a protected money making area as a back up when you are under attack
2. Build only the best defense buildings with power plants in a corner somwhere surrounded by surface-air guns
3. build up only the best tanks you have, occasionaly making raids with aircraft to destroy your enemies their ore trucks
4. send nearly all your troops at the enemy base, after you have a sizable army, while building more tanks back at your base and focus on that once base for as long as possible destroying power plants and ore facilities etc

i hear that on generals the chinese rule, the americans suck and the freedom fighter type guys are just hilarious... unfortunately i haven't played generals that much (i'm just giving you my experience from previous games)