Floating like a butterfly and stinging like a bee, [Titania]'s take on DPS is to fill the enemies debuff bar with a few slash procs before they suddenly turn in to a 100k+ bleed number.

Core:

The build revolves around the [Razorwing Blitz] augment, providing a massive boost to base fly speed and attackspeed for the small price of throwing out a few skills here and there to keep it running.
To power up the augment you need strength and duration, range can be dropped due to not helping a dedicated DPS build. On CC variants range is to be considered but there's much more reliable CC in the game.
Usually, with the amount of firerate blitz provides you'd run out of ammo quickly, that's why arcane Pistoleer is there. Giving you infinite ammo for 12 seconds means you can hold the trigger and unleash hell.
Arcane precision allows you to remove [Hornet Strike] from your pistols to make room for other, better mods.
[Speed Drift] is just there as pure flex. Cast speed is nice for spamming 1 and the boost to sprinting works on your 4... not that you'll sprint often with it outside open world content. Mostly the mod is there as a testament of how bad exilus mods are for the most part.

Alternatives: Higher strength can be achieved with using blind rage instead of transient fortitude and maxing the efficiency mods. Good for simuflex but problematic in practice.

Non-Alternatives: [Energy Conversion]: Although often recommended as an amazing [Titania] mod the strength boost from [Energy Conversion] doesn't actually boost the damage of your weapons, it will however increases the [Razorwing Blitz] effect so maybe it's worth considering in some variants but I haven't found an optimized build that can utilize it.
[Primed Sure Footed]: [Titania]'s 1 offers her full status immunity including knockdown immunity, and as spamming it on yourself is both the fastest and energy wise cheapest way to maintain the 4 buff you're gonna be doing that anyway.
Damage reduction mods, [Aviator], [Aerodynamic], [Ironclad Flight]: If you're facetanking enough to justify these then I donno what to tell you.
Arcane velocity: [Razorwing Blitz] provides so much attackspeed that you won't even notice velocity, its impact on the DPS is minimal.

Economy:

To counteract the skill spamming aspect of [Razorwing Blitz] you need quite a lot of efficiency. R4's of both mods because initial casts can't be cheaper than 25% of their value (175% eff) and duration is positive.
If you go careless with spamming 1 for blitz you can still run out in which case zenurik, brave, pads or all of the above will get you back in to flight range in no time. Kill fast enough while being careful with your blitz upkeep and you'll have no issues maintaining 4 permanently.

Survivability:

Titanias small size while in pixie mode and the passive evasion that 4 provides are already good enough survivability with stray shots being taken care of by shield gating. [Rolling Guard] is used for moments where you want to be sure you can land headshots to keep the pistoleer buff on. It can also be used to get away from trouble. On top of that you have your operator that can heal anything that seeps though or to CC enemies with lockdown.

Subsumes:

Which skill to swap? Either 2 or 3. Neither are useful.

Roar: Roar's a lazy choice but it's the biggest reliable increase to slash procs you can add.
Eclipse: Eclipse's a larger damage increase than roar but it's incredibly unreliably while flying about.
Dispensary: If you commit heavily in to strength and are going to just camp a single area equipping [Equilibrium] and subsuming dispensary isn't a bad idea although it basically gives you nothing in shorter missions.
Any raw damage increase: Usually there's no point building for raw damage when you're doing slash but on a dedicated raw damage build, sure it can work.

Non-Alternatives: Empower: Same issue as [Energy Conversion], although the razorwing augment will be buffed the damage of your weapons will not.
Pillage: Solid shield gate reset (Which can be done with a single sentinel/secondary augur mod and your spammable 1) and strip that's not really needed when you stack slash so quickly (useful on raw damage builds).
Anything that needs range: Yeah, not on a no-range build.

Gameplay:

Cast 4, cast roar then cast 1 (by holding it) on yourself between 1 and 3 times. Use space+shift to trigger [Rolling Guard] without wasting your blink. Then go around pointing in the general direction of your enemies and fill the room with thousands of pewpew's.

Q&A:

Q0: Every time I press shift I keep slamming in to walls...
A0: Don't press shift to sprint. Use sprinting only in open world content or anywhere where you know you have enough space to turbo. [Titania]'s normal movement is more than enough for most missions and if you need to traverse tricky corridors you can use the operator.

Q1: I keep getting stunned by smashing in to walls.
A1: Have your 1 up all the time, it makes you immune to all statuses, including the staggers from smashing in to walls.

Q2: I keep getting killed and....
A2: Git Gud.