GDI Tips:
-Mammoth tanks have two cannons and rockets. Use the cannons on buildings and the rockets for infantry.
-Patch's tiberium flechette pistol may not look like much, but it packs a powerful punch against vehicles.
-Minigunner officers are excellent at helping to detect enemy stealth tanks. Fire a spread of gun fire across the battlefield, and any stealth vehicle hit will usually glimmer a bit more brightly when struck.
-Make sure to support Sydney (with personal ion cannon) with a Havoc or a minigunner, as the PIC has a long reload time and will need anti-infantry support.
-Support you armor with engineers. The mammoth tanks are massively powerful, but without engineer support, Raveshaws and Black Hand lasers will rip right through it.Nod Strategies:
-Stealth and speed are your main weapons. Vehicles are less armored, but they cost less.
-Three or four flame tanks are a force to be reckoned with.
-A stealth trooper with a nuke beacon is a very deadly thing.
-The chem trooper is in a fully enclosed suit, so don't be afraid to use tiberium fields to your advantage. No other infantry can walk through them.
-Keep moving; GDI's armor is strong, but it is also slow. If you stay out of range, you should be able to do massive damage to them from afar.
*All tips and strategies are from Computer Gaming World and Prima's Offical Stragey Guide for C&C: Renegade.