Hello there. You have probably heard how bad True Strike is. However, it has one VERY important use. The arcane trickster roque can take true strike as a cantrip. They can use this to use their sneak attack, providing an actual use to True Strike.

Quote from Underfan8 >>

Hello there. You have probably heard how bad True Strike is. However, it has one VERY important use. The arcane trickster roque can take true strike as a cantrip. They can use this to use their sneak attack, providing an actual use to True Strike.

 This was always an edge case thing. Any rogue would be better off using sneak attack through having allies adjacent to them or through a bonus action hide. Then they get to attack 2 turns in a row without worrying about concentration.

And this is especially true for Arcane tricksters, who arguably have access to better spells to gain advantage. 

But now with Tasha's, they get an ability called "Steady Aim," which lets any rogue gain advantage on their attack at the cost of their movement and a bonus action. 

So True Strike was never very useful, and now it has lost even its niche potential. I really hope it gets reworked. 

Using an Action for a potential bonus (being a Concentration spell you need to be wary) in the future is awful. By itself the cost of an action is insane. Bonus Action Hide is better there, if that’s your playstyle.

Fearie Fire is a better option if you want an Action Spell. Still is concentration but last one minute, has a Dex Save, but is an AOE effect that gives you and your party Advantage. You would get sneak attack even on a reaction opportunity attack against those "painted" enemies. 
Now that isn’t quite available to AT rogues by default but Magic Initiate or Fey Touched feats could help. 

My opinion is however that Rogue’s Action (tied to their potential sneak attack) is too precious to waste on a spell for which you already have little slots for. Get a cloak of elvenkind or work on having great sneak and use the Bonus Hide action after your attacks. Or use "allies" or your Familiar’s Help action to enable your sneak attack.

Rogues are cunning, I’m sure you can figure something better then True Strike hehe

There will be occasions where you can't use cunning action to hide e.g. in an open field in daylight and there will be occasions when you know you will not have an allie next to a bad guy for your next  turn but both of these happening at the same time will be extremele rare, certainly not worth learning a spell for.

For a rogue I wish true strike worked was a bonus action and applied to your attack on the same turn though maybe that makes it too powerful for characters that have little use for a bonus action.

Oh how I wish I could easily self-enable sneak attacks when Hide isn't an option!

There are few options for that, like Grappler Feat, or knocking the enemy prone (adv. on melee) or blinding them, somehow...

I feel that there will be time where a Sneak Attack is just not possible, even when carefully planned for. In those rounds, I would probably suggest preparing for the next round, or hold your action for when a sneak attack becomes possible during that round (using all your action economy, but better then doing nothing).

Quote from Hyrkali >>

Oh how I wish I could easily self-enable sneak attacks when Hide isn't an option!

There are few options for that, like Grappler Feat, or knocking the enemy prone (adv. on melee) or blinding them, somehow...

I feel that there will be time where a Sneak Attack is just not possible, even when carefully planned for. In those rounds, I would probably suggest preparing for the next round, or hold your action for when a sneak attack becomes possible during that round (using all your action economy, but better then doing nothing).

 I mean, now we have Tasha's "Steady Aim" ability, so its pretty easy now. Just have to have a rogue that can stand its ground a little.

In my book True Strike never has been and never will be useful without being buffed with a house rule/homebrew.  The limitations are simply too crippling: needing concentration and being useless if the target dies before your next turn pretty much makes True Strike unusable for me.  As a Arcane Trickster I would rather just cast 2 Booming/Green Flame Blades even if I can't get advantage.

I dunno about True Strike on an Arcane Trickster, especially with the Steady Aim optional class feature from Tasha's Cauldron (bonus action advantage on a ranged attack, can be used in the same turn). We also already have ways to get advantage, namely Hide, which again can be used as a bonus action.

The main use I've found for True Strike is on a sorcerer on top of a bonus action spell or via Quickened Spell; you can use it to prep advantage for the next turn even while doing something else in the current turn, and it can be stacked with Seeking Spell. It's potentially expensive on Sorcery Points (up to 4) but having advantage and a re-roll can make a huge difference when you're dropping a higher level attack spell, as there's nothing worse than burning a high level spell at missing.

You could make the same argument for a Trickster I suppose, since we have so few spell slots, so there's still some use there, but the majority of spells I take on tricksters aren't attack spells; I much prefer control and other shenanigans like traps, tricks and utility spells.

Otherwise the main time you want to use True Strike is when you're anticipating combat, as it's a cantrip so it costs nothing to use it continually before a fight begins, so you have advantage on the first turn. Again though this isn't necessarily useful to a Trickster as you have other ways to get advantage, but it might work for a melee Trickster who does not expect to be able to sneak into range, or to have as backup if the enemy spots you.