when you come out do DP always make sure that you have atleast 10 stacks,

personally if i was fighting npcs with terran i would use

pthor
fenrir
nirv
dummy
dummy
dummy
dummy
dummy
dummy
dummy

a dummy stack is just 1 of a low PR ship such as fodder or aries 

 D.Pike Destroyer	  38 	  0 	  38 
 D.Hammerhead Frigate	  13 	  0 	  13 
 Tiger Destroyer	  27 	  3 	  24 
 Strafez Queen	  1 	  1 	  0 
 Strafez King	  1 	  1 	  0 
 Manta Corvette	  1 	  1 	  0 
 Large Strafez Runner	  1 	  1 	  0 
 Large Strafez Fodder	  1 	  1 	  0 
 Small Strafez Runner	  1 	  1 	  0 
 Eel Fighter	  1 	  1 	  0 

this is the type of fleet i use for attacking
make sure you read up all the ships from all races that way you will know what to use to counter somebody 
its all just a guessing game at the end of the day but if you know each ship for each race it helps making a better guesstimate on what they will have