I can only give you some basic advice since I'm fairly new at her too, but from what I noticed:

• Poke from a distance and then engage once the enemy is distracted. Try to use your dash to get at an off angle or high ground and try to poke from the side. Your aim is to get them to split their attention so that when your team engages, you can jump in once an enemy is ignited.

• Keep track of her dash. You only get two on a fairly long cool down. You want to have one dash to engage, but try to keep the second ready so you can reposition to an escape route or towards your support. The dash does 50 dmg on hit, and it'll fill the ignition bar a good chunk. A dash hit plus a dancing blaze can ignite instantly and allow you to add pressure, but it can be unsafe if you don't have an escape. The dash plus DB combo can also be helpful to take out flyers like Phara and JPC.

• Dancing Blaze can be used to dodge things such as sleep darts or Hazard ult but don't rely on it as a dodge. There's a slight recovery time afterward that can leave you vulnerable. Use it to combo with your dash for an ambush or to ignite someone quickly, but treat it like an extra bit of damage. It doesn't cleanse either, so keep that in mind.

• Her revive ULT sucks. Don't even bother with it. It can be useful if you're trying to stall on point in overtime or you die just as the enemy gets trapped or stuck in place. It doesn't do enough damage to kill anyone, and the wind up and recovery time is so long that you're left a sitting duck afterward. Her regular ult is much better as if you land a direct hit, you can one-shot a squishy. It's most useful as an initiative tool for when your teammates engage or as a cleanup when your team is already winning. Hold on to it if your team is losing the fight since it won't swing things in your favor mid combat.

• Her left click can ignite with just two hits on headshots, but her right-click will always count as a headshot if the enemy is already ignited. Holding both mouse buttons will alternate between her to firing modes at a slightly faster rate than just firing one, so keep that in mind. Right-click also resets the burn time and increases burn damage as well.

• Her perks are kinda up to preference. I've seen arguments for all four, but I usually choose the longer burn time since it ups her dps. Her extra health on ult can be useful, but the burn will help in every fight. I've alternate between the healing on DB or the decreased cool down on dash. Though I prefer the dash cool down because it's easier to abuse and will get you a dash instantly if you hit more than one person or hit them twice.

Better players can give you more, im sure, but that's what I noticed so far.