REPAIR YOUR CONSTRUCTION YARD: Always keep a slew of engineers standing sentinel around your construction yard. Keep enough their to frustrate any enemy attempts at squishing them all. Then when s/he tries to destroy the construction yard keep repairing it with your engineers. You would be surprised how much fun you can have with this technique. I have had people sitting with their tanks in my base constantly firing at my yard while I keep repairing it whenever it hits red damage. Meanwhile I am chewing on their tanks with my own. What ends up happening is all of their tanks are destroyed and they accomplished nothing. Not a bad trade off eh?

ENGINEER RAIDS: In my opinion this is an outdated technique, but can nonetheless devastate an unsuspecting, or unprepared opponent. To really pull this off, a couple engineers is not going to do it. Try 20 or so. All loaded in APCs or Chinooks and transported to the opposing base. Unload and capture. Unlike the original command and conquer, engineers in red alert do not capture a structure immediately. It must be in red damage before you can capture it, but fortunately if it is not the engineers put some serious damage into it. It will take about 4 engineers for each structure. The more you bring the better though since you have to be mindful of defensive structures and (cringe) DOGS.

BY LAND, AIR, OR SEA: Your engineers can reach the enemy's base by land (walking and APC), air (chinook) or sea (transports). But, I have encountered that sending them by sea (in transports) is often the best method. This is especially true for a map like A Path Beyond where the entire map is surrounded by water and there is coastline located conveniently by the opponents base. Here's what to do: Toss 5 engineers into a transport. Move the transport next to their base. Deploy the engineers where they will be closest to capturable structures (like advanced power plants) and capture the nearest building. Also remember to have a structure ready to be placed so that once you have captured the power plant or whatever you can place your new structure down and have a larger foot in the door so to speak. I would suggest a TESLA coil for this purpose but if you feel more inclined to put down a kennel, so be it. = )

DEFENDING YOUR NEW STRUCTURE: You worked so hard to capture an enemy structure, don't let that go to waste. As mentioned above have another structure (like a tesla coil) ready so that it can be built after the engineers do their job. The tesla should ward off weak infantry attacks or even 1 or 2 tanks, but it isn't going to stand for long without you taking further measures. My favorite thing to do in this situation is to build walls like nuts. As the tesla zaps away at enemy units and structures, place walls all over the enemy's base. This works well for many reasons. Not the least of which are blocking the shots of the tanks that are trying to destroy your tesla, and blocking up your opponent's base. With walls everywhere, they won't be able to get ore trucks in and out, won't be able to move their herds of tanks through their base, and won't be able to get their own engineers to the buildings that need to be repaired.