GDI is at a disadvantage
when it comes to attack, they get to the enemy base, only to find it
under cloak and impenetrable due to mega defense. If you play GDI
you must make some attempt on an early attack, don't let NOD
player's intimidate you by saying oh you rushed me. Tell them well
if you let them get a shield generator you're doomed. Well even if
they do, you're not doomed. So you make an early attack, usually
with Jump Troops, they are flying and therefore hard to stop in the
early game and can take out refineries, or their construction yard. Crippling
the enemy. If this doesn't get you victory, you will quickly need to
switch to defense and stop all attacks. Build concrete slabs
throughout every square inch of your base. And as far out around
your base as possible to prevent unwanted subterranean units
entering your base. Build several Detectors and remember to activate
them. Then switch to building a mass of defense around your base, be
sure to cover the whole perimeter with SAM sites and Rocket sites,
if they attack you with a whole load of infantry build several Vulcan's.
If you feel the need invest in a Firestorm Generator. If you are
setting up a second base, and can live without radar destroying all
your power plants while your firestorm generator is on, will let it
stay on forever. But make sure your other base is well equipped
first and learn to live without radar. Once your defense is organized
with a large number of tanks, a MK2 and many Hover tanks. You're
into stage 3. Prepare for war, here you should be beginning to build
a mass of troops, bombers, fighters, tanks etc to attack the enemy.
When you send in your force, be sure to send a huge force of at
least 50, and include 3+ detectors, and turn them on at various
stages of the entering of the enemy base. Use your bombers once you
can see their buildings and try to take out power plants to remove
the stealth threat.
NOD are the king when it comes to trickery, sneaky tactics and are
hard to kill. Make sure in the early game you have a large amount of
anti air, and ground defense troops, and SAM sites/anti troop sites
as soon as possible. You'll need to stop the early rushes made by
GDI. Builds tons of power plants and space them out, make sure you
have enough to build a cloaking device. Make sure your whole base is
cloaked. Build multiple cloaking devices. Cloaking is your key to
winning. After you have tons on anti air and anti troop stuff, go
into the production of mass obelisks of light. They are great. Try
to have detectors around too, so you can see if any enemy detectors
are near your base and just sitting there. Spread out and build a
second base, save up enough money to build a cloak and a few
defenses and create a second and possibly third base if the map is
big enough, that should provide you with adequate come back grounds
if 1 base is destroyed. Plus its hard to find a cloaked base. You're
now ready for war, a collection of flame subterranean tanks works
well, so do subterranean apc's with engineers and a commando. Use
the engineers to steal enemy building then build base defense around
the area or just sell the building. Try destroy 1 building or use a
multimissile, to create a hole in their concrete where you can get
into their base. If you can't get in from under the ground, you'll
need to launch a combined air and ground attack, send in small
forces to make him waste his proton cannon. Remember stealth and surprise
attacks and your key to victory.
General Tactics
Always have a large supply of tiberian, don't overbuild, try to keep
at least 1000 in storage in case of emergency.
Build multiple refineries, spread them out, do the same with your power plants.
Don't clump them. So they can't all be destroyed at once.
Use your big guns, always have an ion cannon / multimissile built
and a hunter seaker. They don't cost tiberian to stay up and
running. But remember you wont be using them if you do the firestorm
trick.
Have around 10 harvesters as soon as you can, but remember not to
build them first or you won't have any defense. If you have the
economical advantage, you'll usually win the game hands down.
Keep sending small attack forces to keep him on the defensive.