While playing as the Scrin in Campaign, Multiplayer, or Skirmish mode, it is usually not possible to place buildings within a thunder storm produced by the Storm Tower. To get around this, power down the Storm Tower, and place whatever desired next to it (another Storm Tower is recommended). This strategy will help improve your base defense.
There are some buildings that you can only build once (for isntance, Statue of Kane and the Redeemer/Reclamator/Hexapod Facility). However, you can actually build more then one. Get additional Construction Yards (build MCVs at your War Factory), then place the Construction Yards. You now have more than one building queue. Start making the building you want more than one of at all your Construction Yards. When they are done, place them. The more Construction Yards you have, the more statues or facilities you can create.
Play as NOD and drop several mines in Tiberium fields. Throw in a Cataclyst Missile and you will not only blow up the minefield, but also all the mines in it. The results are devastating and can eliminate all the enemy ground forces. This is very useful for making short work of the enemy's super unit. Also you can use the Cataclyst Missile on a refinery to destroy it with one hit. This works only on Tiberium manufacturing structures.