[SHOGO - Mobile Armor Division]
General
 
       
  Get in the habit of hitting U all the time
Trust me. You'll save yourself lots of pain if you hit "U" frequently to deselect any selected objects. In Geometry Mode, you should train yourself to hit U after every operation if you're working with different vertices.

Save often
Don't learn this lesson the hard way. Ctrl-S is your friend.

Use the pointer

Use the node view
Relying on the
node view to find grouped objects or individual objects can save you a lot of time, particularly once you start renaming nodes. Get accustomed to using it whenever appropriate.

Be consistent
Consistency is critical if other people might have to work on your levels (which, in most cases, they will). Come up with simple, easy-to-remember naming conventions and stick to them.

Use Advanced Select
The Advanced Select option in the Edit pulldown menu (Alt-A) can save you lots of time and effort, particularly once you've adopted consistent naming conventions. With Advanced Select, you can select an object or group of objects either by class (e.g. Light, DirLight, ObjectiveTrigger, etc.) or by name.