NOTE: Roar has much higher damage but needs to be upkept. Decide which you prefer.

This is my [Titania] build I've been using for last ~200 hours of gameplay, 'ported' to [Titania Prime].

It's aimed at going into Razorwing mode as quickly as possible, stacking up Blitz and staying in it for entire mission.

This build is more than viable for nearly every mission in the game except for Arbitrations (explained at the bottom) and maybe Eidolons.

Typical mission goes like this:
1. Zenurik at the beginning until you have ~200-300 energy.
1.5. If you took Empower, use it.
2. Hit enemy with status weapon for [Growing Power] proc.
3. Enter Razorwing.
4. Stack up Blitz by casting Spellbind.
4.5. If you took Roar, use it.
5. Obliterate everything around you.
6. If Razorwing Blitz buff is running out or you run out of ammo, go to 4.

If you need to activate console/revive/pick up Ayatan you can go into Spoiler mode, no need to drop Razorwing.

Buffs from Tribute are generally unnecessary for 90% of the missions in game and bit clunky to use, but might have some utility in more difficult runs.

Prioritize Thorns (for 50% damage reduction) and Dust (for 50% evasion) if you decide to make use of Tribute. Full Moon is decent for keeping Razorflies up but you ultimately don't need them. Entangle isn't that good because you want to stay out of enemy range, not try and melee them.

To survive, move constantly. Use your incredible speed to weave in and out of enemy range. With your tiny hitbox and innate evasion you can deal with many enemies at once even if Razorflies are all dead. Abuse shield gating, play more passively once your shield goes down.

About Arcanes:

Arcanes used in the build are Precision and Pistoleer.

Pistoleer in particular is really important to have.
Rank 3 will ~triple length of your bursts.
Rank 4 will prolong bursts by ~6.6x
Rank 5 will grant you nearly infinite ammo as long as you kill something with near head shot (i.e you can shoot Grineer's back and it will trigger despite technically not scoring headshot).

Precision maxes out chance to trigger at rank 3, with further ranks increasing duration (though it's trivial to keep up) and damage (200 -> 250 -> 300). In short it's nice to have it maxed out but you can safely stay at r3 to save plat.

If you can't spare Umbral forma for fancy [Vitality] and Intensity, feel free to use regular variants.

If you can't afford to max out rank 10 mods, get them all to rank 8 first. If you decide to upgrade them further prioritise Narrow Minded = Transient Fortitude -> Primed Continuity -> Umbral mods -> [Primed Flow].

About Auras:

Don't bother with [Pistol Amp]. Damage increase looks nice on paper, but really scales pretty badly. With rank 10 [Hornet Strike] maxed out [Pistol Amp] increases damage by ~8.4%, with r5 Precision active increase is only ~4.3%.

[Growing Power] will increase your damage by ~11.9% (when at 210% Strength), and also increase your fire rate and movement speed thanks to Razorwing Blitz. Bonus ability Strength is also usually more welcome in squads.

Corrosive Projection - up to 18% direct damage increase depending on enemy armor. Not bad, but the increase doesn't apply to slash procs which are [Titania]'s best weapon against armored enemies. While worse than GP, its still a good choice benefitting teammates a lot.

About Exilus:

[Preparation] is really nice mod, because it let's you to [Reach] threshold at which you can infinitely sustain Razorwing faster. Maxing it out is a waste though, because all frames start with 50-150 energy already. With rank 3 I'm using in the build you will already start out with half of your total, which is plenty.

Other suggestions (you may need to forma third time to fit them though):

Aviator - ever popular, 40% damage reduction in Razorwing. May save you from death at higher levels once your shields are down.

Power Drift - bonus 15% Ability Strength. Bit of extra damage, fire rate and movement speed. Decent choice.

Handspring - more or less [Negate] interruptions from Fire eximus enemies and ramming into things. Also pretty good choice, especially since knockdowns can quickly lead to death.

About Helminth:

Since Lantern is nearly completely useless we can finally replace it with one of the more useful Helminth Abilities.

Empower - 50% Ability Power for 25 energy. Extremely cheap one time cast for ~20-25% more damage and fire rate. Lazy option.

Roar - 30% more damage for 30 seconds before mods (!). Far more powerful (and helpful to teammates) than Empower, but has to be recasted. With mods, drains around 0.6 energy per second so keep that in mind.

Xata's Whisper - 26% more damage for 35 seconds before mods. Not bad but unlike Roar it won't affect slash procs. Upkeep ~4 times lower than Roar.

Null Star - in this build means 50% damage reduction. If you're struggling with survivability may help a bit.

Nourish - at 250% ability power grants 125 hp and 125% toxin element for 50 energy. Bonus damage translates (assuming 3x 60/60 mods on Dex Pixia) to around 32% increase (after mods). Better take Xata's Whisper.

Master's Summons - in theory, it could help with keeping Razorflies close and alive. In practice, I have not tested it so I have no idea if it even works.

Infested Mobility - if you felt like you were going too slow, now you can shame Archwings in open worlds and hit every wall everywhere else even faster.

Recommended weapons:

Since you'll spend most of the time inside Razorwing they're not that important, but there are few useful things to consider:

Kitguns with Pax Bolt - strong, free 30% Ability Strength and capped Efficiency. No reason not to use one if you're able to get it.

Vaykor Marelok - accurate, pretty fast, decent damage, can easily reach over 100% status chance for quick Growing Power proc.

Staticor - great at applying [Growing Power] and not much else.

Weapon modding tip:

Consider putting [Seeker] on your Dex Pixia. Its value is incredible, letting you to mow down enemies in lines and shoot through doors and windows.

Arbitrations - because drones are still unable to be harmed by [Dex Pixia] using [Titania] is not advised. Dropping Razorwing, killing Drone, reentering Razorwing and stacking Blitz again every 15 seconds is far too annoying to be enjoyable. I recommend (with heavy heart) that you use some other frames for them. [Mag] and [Vauban] should fill that gap nicely.

Though if you want to really go for Arbitrations as Titania, swap out Blitz for Natural Talent, drop most duration mods (only so you have ~2/s drain + low Razorwing activation cost) and get more tank mods like [Umbral Fiber] and [Aviator]. But that's completely different build.