Rush/Turtle/Tech/Steamroller
My first plan of any RTS or Stradergy game- Everything from Age of Empires to Civilization and currently Total War: Shogun 2 is to quickly mass a army and take over all nearby outposts, resources and undefended cities.
The second step is to stop and consolidate my forces, cities and fleets, if applicable. After this, i spend all avalable resources on gathering more resources and defending my base. All of this takes place while i attain Technical Superiority.
After this, Step three starts. I begin to build a massive army out of the resources and Tech i have gained in Step 2. All of this while defending my outer borders with the once-offensive army. With my now tactialy superior army, i begin steamrolling. if at any point my army fails, i quickly build another one, thanks to my masses of resources.
For example, in my current campaign as the "Shimazu" (Samurai builders) i have conquered the entirety of the small island they start on. Since the island only has one good entry point, this is where i am currently defending. I am now in the process of starting Phase 2, and have two of the 7 Trade posts all to myself.
Another example is "The Lord Of the Rings Battle For Middle Earth 2: Rise of the Witch King"
In this, i either play as Angmar, The Elves or the Dwarves; the stradergy in them is mostly the same.
For each Faction, they all field powerful archers, with Angmars having the best Strength/Cost ratio. I quickly Build all the farms/trees/Mines/Mills i will need, and tech up to gain the Archer unit and the Upgrade aplicable to them; Ice Arrows for Angmar, Silverthorn Arrows for Elves, Fire Arrows for Dwarvern Men of Dale/Forged Axes for Axe Throwers and so on. Then, i build a wall of towers and fortify all of my men inside those towers- This creates a nigh- Impregnable wall for the enemy to bypass. From there i can attack the enemy at my liesure.
However, i usialy lose the match at this point, cause i suck. However, i once sucessfully held Helms Deep with three Max Upgraded Mirkwood archers against three of my friends... for three hours. They got so bored at being unable to defeat me, they Raged.
the third stradergy i use is a modifyed version of the above tactics.
Instead of spending resources on Teching up my Faction, i build ab out Twenty training buildings, and build a quick army of Cheap, Expendable units and Charge the enemy base. At this point, my army either wins or dies, taking a great number of the enemy down with them.
But by the time that the enemy has rebuilt his army, i allready have another army build from my ~20 baracks.
I just steamroll.