For transport missions, you need to pack the 
biggest bang into the smallest number of units. 
Choose your most experienced units, even if they 
aren't packing your most powerful weapons. 

Be sure to leave some units near your base 
to defend it. After you've completed a mission, 
your next mission begins with your units in their 
final locations. If all your units are a long way 
from your base, and the next scenario begins with 
your base under attack, you're in trouble. 

It's not a good idea to have the same type of 
weapon on all of your units. Combine the types of 
weapons in each group to make sure they can handle 
different threats.