Generally, I believe that you should have an option to reach different kinds of enemies.

• Close/middle-range and long-range options
  
• Buildup and instant attacks
  
• Mobility to set up your most damaging option (closing or putting the distance)

Engineer gaming
Orange is centred around its Atlas, so I believe, that setting it up is the key.
Burst Scour
What I used to annihilate the boss on Binding 6 and receive a cool hat earlier.

• Punctuate (lance) for long range and buildup option
  
• Passage (hourglass) for close range and instant option
  
• Dash as a neutral option for setting up the hourglass and getting distance for the lance

How to do it:

1. Saving up Survey for a level or two (1-2k Survey is enough, I usually get 10k before the first boss)
   
2. Picking survivability and orange mana perks
   
3. When there are enough enemies in your sentry’s Atlas’ range, use the hourglass and annihilate
   
4. Pick up your Atlas, rinse and repeat

I found the signature spell not too reliable (skill issue)
UPD: Orange Signature looks nice as a supportive option and against stationary enemies
Also try aiming the beam under yourself for better precision, because it targets the closest surface

In multiplayer Orange Ink hard carries early/midgame (first 1-3 appendices) even at Binding 50, assuming careful use, then the numbers of Yellow and Pink are just ridiculous.
Later Orange becomes mostly supportive, don't forget to encourage your teammates to stand near your Atlas for extra armor/healing.

• D20 is the best Generator for me yet
  
• Almost every AOE Spender or Eclipse is ok. Btw Overrule seems weak
  
• If you plan a long run, pick infusions of other colors to get their buffs after your build is mostly ready
  
• DON'T pick too much speed talents, since later in the game it will be hard to pick up your Atlas, leading to losses of Survey. Possible solution is to upgrade your Movement Spell as much as possible instead