I have been playing a Fighter with the Battle Master archetype (PHB, p. 73-74), and most of my companions in my party are new to the game. I was trying to play a supportive-type character, even if I'm playing a Fighter - I'm mostly shoving people so they can attack with advantage and playing with the Polearm Master feat (and the Sentinel feat in the future) so I can zone out monsters and protect our Sorcerer and Rogue that don't know how to position very well.

Our DM chose to not allow sources other than the PHB for characters.

With Battle Master, I intend to get the Trip Attack, Precision Attack, and possibly Commander's Strike maneuvers so I can keep being supportive and making them feel useful.

Commander's Strike says:

When you take the Attack action on your turn, you can forgo one of your attacks and use a bonus action to direct one of your companions to strike. When you do so, choose a friendly creature who can see or hear you and expend one superiority die. That creature can immediately use its reaction to make one weapon attack, adding the superiority die to the attack’s damage roll.

Action economy wise, Commander's Strike seems to suck. Mainly when I am the person hitting the hardest in the party. At 4th level with Great Weapon Fighting, a Glaive, and Polearm Master (even if I go for 18 STR instead of Great Weapon Master), I would be doing more damage with a Glaive Attack + Polearm Master + Trip Attack than if I used Commander's Strike and allowed our Ranger to attack with Hunter's Mark and Colossus Slayer or allowed our Rogue to attack with Sneak Attack. Besides, with Trip Attack I can actually choose to use the Superiority Dice only after I hit, and it doesn't spend my ally's reaction.

When is Commander's Strike worth it? Are there actual scenarios where a considerably optimized Fighter would choose to forego one of his attacks and a bonus action so an ally can attack? I will probably still be using it just to make them feel good about doing 3d8 + 1d6 + 3 damage at 3rd level, but I would like to use it knowing it's actually my best choice.

Party Context

Our party is currently going to 3rd level, we are playing Princes of the Apocalypse. There are lots of people, the composition is: Tiefling Sorcerer, Human Dual-Wielder Ranger, (Some-kind-of) Elf Rogue, Dragonborn Paladin, Half-Elf Warlock, Dwarf Cleric, (No-Idea-What-Race) Monk and me, Human Fighter.

The Rogue has a +1 Longbow, which I forgot to include in my math, whoops. The Ranger is dual-wielding two Rapiers (and has the Dual Wielder feat).

When another's attack would do more damage/be more impactful than yours.

Not going to lie: I don't feel like going through your party and doing the math, but suffice it to say that there are times--even when playing a Great Weapon Master--that someone else's attack is expected to do more damage. Like when you can direct your Sharpshooting ranger to take a shot at the dragon overhead that you can't reach. Or when your L15 rogue is doing 8d6 or so on a hit.

I recently played a Battlemaster in a L18/19 party--being able to forego 1 of 3 attacks to give the rogue a sneak attack for 10d6 was pretty nice. (Especially when my first attack had been a Distracting one to ~double the rogue's chance of critting and doubling those dice!)

At low level, though, you're right: your attacks are generally going to have more "OOMPH" to them; delegating one to another party member is likely to be a strategic move (interrupt a caster's concentration when you can't reach them or ally has a time-limited buff, for instance).

Commander's Strike is worth it if you can direct your Rogue to attack.

Take a look at this question/answer: Do rogues get sneak attack damage added to attacks made outside their turn?.

Giving the party Rogue an extra Sneak Attack is a big deal, and will only get bigger as you level up. If your Rogue has no other way to get an attack as a reaction, Commanding him or her to attack will usually do more damage than a Fighter will do with one attack and a Bonus Action. If this is not true for you at your current level, it certainly will be once the Rogue gains a few more Sneak Attack dice.

In your current party situation, rarely

Since you have optimized your Fighter for damage dealing, rather than for support, your DPR will be more effective than most other party members (particularly in Tier 1 play) unless

• There is a ranged attack needed for an enemy that you can't reach,


• 
  

  You are unable to move (grappled/restrained) and need your ally to
  attack whomever is grappling/restraining you.

  
  
  

  In that second case, rather than using your action to try and escape the grapple (particularly if the enemy has a higher strength than you) you are using your ally (most likely the rogue) to kill the grappler rather than you just escaping without doing damage to the grappler.

  
  

Some times that Commander's Strike can still be useful

Let's look at the costs of Commander's Strike:

When you take the attack action on your turn, you can forgo one of
your attacks and use a bonus action to direct one of your companions
to strike. When you do so, choose a friendly creature who can see or
hear you and expend one superiority die. That creature can
immediately use its reaction to make one weapon attack, adding the
superiority die to the attack's damage roll. (PHB)

You giving up an attack, and a bonus action, is a non-trivial cost.

Since @nitsua60 has already covered your Rogue's damage boost from both Sneak Attack damage and your superiority die's 1d8 damage (1d8 + 2d6 + attack dmg) I will cover a case where your Ranger has Hunter's Mark up, you offer Commander's Strike, and the Ranger has Colossus Slayer. Let's see what the Ranger does for you with that free / reaction attack(on a hit):

Weapon(1d6)¹ +1d6(Hunter's Mark) + 1d8(Commander's Strike) + 1d8(Colossus Slayer) + Dex mod(3)(at Tier 1, could be 4)

That reaction attack compares favorably to your attack, but not to the degree that it should be your choice every time. It would certainly be a good choice if the Ranger is engaged with the critical enemy that you can't get to this round.

For Support builds, Commander's Strike grows in usefulness

On a slightly different build, my Battle Master (5) often gives CS to party's Barbarian; he uses a Maul and has two attacks. (My BM uses the Protection fighting style (he's more Tank/Support than DPR in build). There are numerous times that we are better off giving the Barbarian another attack (as a reaction), particularly when he is Raging and also gets the Rage damage bonus on successful attacks. The other one my GM boosts is our Gloom Stalker Ranger when Hunter's Mark is already up.

¹ Presumes short sword on your two weapon fighting Ranger

The math of who can do the most damage is not always the most important thing when considering when to use Commander Strike. Think of some of the following scenarios:

• You are out of range of the enemies but your party members are in range (e.g., you were farther when the fight started and couldn't get into range in a single turn).


• There is an enemy that would die in one hit near an ally you cannot hit. Generally speaking the best things to attack at the things closest to death so they get less turns to act (meaning less attacks, meaning less damage taken). If your ally is in a situation to land a killing blow and you cannot then using Commander Strike is a good idea.


• There is a particularly dangerous enemy you need to take down as quick as possible that your allies can attack that you can't.

The common theme is that there will be times when the thing you should or would want to attack you won't be able to but someone else is. This will matter less the more mobile you are (e.g., you are faster or you take the Mobile feat), if you also have ranged attacks (Javelins are great for this). If the opposite things are true for less of the attackers in your party (they are not very mobile or they also don't have ranged attacks) then there are less times when this will be useful.