Strategy

Tifa is an agile close-range fighter with fast pokes and a decent aerial moveset, but lacks effective ranged attacks and utility against lingering projectiles. Her strengths shine when fighting on the ground.

Offense (Ground)

Poke with Waterkick and use it's Somersault HP link. It combos into assists and is difficult to react to with Assist Change.
Utilise her fast ground dash to close distance and provoke a response from the opponent. They will want to defend against Waterkick, which informs Tifa's decision making.
To get around blocking, mix up with jumps, a Blizzard projectile, a ground HP or Beat Rush feints. The damage on Beat Rush is not particularly high, but it is relatively safe on whiff, teleports behind the opponent when close and it can be easily hit confirmed.

Defense (Ground)

Avoid linear attacks with Tifa's run speed by moving sideways or away from them. Depending on the match-up, this is a safe way to create situations for punishing whiffs and dodges.
Whiff Waterkick to build assist meter faster.
Catch an opponent's whiff with Blizzara from afar, but be wary of assist whiff punishes.
Blizzaga can also be used pre-emptively to force a dodge or punish a reckless dodge. It's slow to come out, but it spawns above the opponent with a max range restriction. So if they're already pre-occupied, Tifa can occasionally benefit from throwing out Blizzaga. It wall rushes on the ground and even combos into Waterkick, Meteodrive and Meteor Strike if she can follow up before the wall rush happens.

Dodge Punishment (Ground)

Ground Dash to follow the opponent's neutral / side dodge and dodge punish with Waterkick > Somersault.
Burning Arrow has enough tracking to also hit neutral and side dodges. It's a single hit HP, so it bypasses EX Revenge. A good move for a decisive read.
Rolling Blaze forward ground dodge, but misses against other ground dodges.
Beat Rush feint is Tifa's primary post-dodge defensive option on the ground. She is invincible during the feint teleport and it can also teleport behind the opponent if they're close enough.
Meteor Strike lowers Tifa's hurtbox, which can be used against air-to-ground dodge punish attempts.

Offense (Aerial)

With the absence of Blizzards and HP links, Tifa's aerial strategies change up a little to accomodate her feints more. Feints become more prominent in the air due to increased HP attack range and more braveries having a feint cancel at the beginning. Her offensive gameplan works similiarly, dashing quickly in the air to close gaps and create interactions up close.

Elbow Smash can be used like Waterkick without an HP link. Good for approaching and poking, it combos into fast bravery assists with the first hit.
Moonsault Kick is Tifa's high damaging midair bravery. Much like Beat Rush, Tifa can teleport behind the opponent by feinting.
Just like on the ground, Tifa can mix up her attack timing with air jumps, feints and charging up an HP (Meteor Crusher in this case). Remember to refresh air jumps with quickmoves.
Feinting a bravery attack during it's startup can punish reflexive blocking, because Tifa can delay the attack long enough to bypass a regular block's active period. Use this sparingly until you have a good grasp on the opponent's habits.
Rolling Blaze feints have a lot of tracking and control a good amount of space below Tifa. Use it to pressure opponents staying below her and call out dodges with the feint followup. Grounded Rolling Blaze has good tracking as well (upwards instead of downward), but sees less overall.
Against grounded opponents, be careful when using Falcon's Dive. It’s relatively predictable in those instances, but has good reward on hit with Kuja, Sephiroth and Aerith assists.

When defending, use Elbow Smash and Falcon Dive to safely build assist meter on whiff. Feint Moonsault Kick early to cover her dodge recovery against punish attempts.

Defense (Aerial)

Elbow Smash is the primary air poke for fending off opponents with least risk.
Use Elbow Smash and Falcon's Dive to build assist meter on whiff.

Dodge Punishment (Aerial)

Charge Meteor Crusher to catch air dodge and late block attempts. This attack has very short range without charging, so make sure to release the HP button after confirming
Rolling Blaze feints can catch dodges below Tifa. Feint the first Rolling Blaze and try to see if the opponent dodged.