Change Battle Screen Size:
While holding L press c-up or c-down

Build Away from Base:
Layout sandbags to the area you want to build at!

Sandbagging trick
Use sandbags to build all the way to your enemies base. Now build some defenses, guns or whatever to take them out! A ton of turrents is especcially effective!

Change Screen
Hold L and press C-Up or C-Down to zoom or un-zoom the screen

Economics 101
Build a Tiberium Refinery. Sell the actual refinery and you will receive $1,000 credits. You end up with an ore truck. You save $200 credits. If you were to build and ore truck through a war factory, it would cost $1,200 credits

Economics 201
Need an Orca but don't have enough money? Instead of buying it, simply build another heli-pad... and then scrap it. You will be able to keep the Orca that came with it and save 450 credits!

Sell Men
Place your Mini-Gunners really close to a sand bag wall and sell the wall. If your men were close enough, and it works right, your men have been sold.

Sell vehicles
Place a not wanted vehicle on a repair bay and put the sell cursor over the vehicle and preess "A".

Be able To Build Opponent's Units
Get your engineer to take over a enemies construction yard and you can build their units

APC Trick
If you're playing as GDI, and you have access to APCs and Engineers, then you can try this trick. Build 2 APCs, and put them each to a C-button. Now build 10 engineers, split hem into 2 groups of 5, put each group on a C-button, and load each group onto an APC. Now, drive the APCs over to the enemy base, and park them next to the NOD construction yard/barracks/airstrip. If the APCs are blown up, it's okay, the engineers will walk out still alive. Send all the engineers into NOD buildings, going into the construction yard first. Now, whenever you blow up a NOD building, they won't be able to replace it. And, if you captured their Hand of Nod or airstrip, then they won't be able to build any more units if you blow them all up.

1500 gold cheat
message: To get 1500 tiberian, set up 5 grenaders and 5 minigunners beside the tiberian factory. Wait till an enemy comes and start attacking the factory. In like 2 seconds your money will raise up by 1500, and your factory will still have full energy if you do this correctly.

Hidden Level
On the GDI mission on the Czech Republic: Level 6. When your playing as the Commando guy, blow up all the sam sites in the beginning. Take the chopper to the far left and as quickly as you can, release the commando. If done correctly, it will say your mission is a failure. Restart mission and you will end up in a hidden level.

Obelisk tower of light tip.
If you can't get past your enemys obelisk tower of lights(laser tower) just take out their power plants and the laser towers will be disabled.

Harvester tip
If you are sick of getting killed by enemy forces when you try to destroy their harvester then attack the harvester with air craft.(Nod-Attack helicopter) (GDI-Orca.) Then your enemy will not attack you.