depend what character you playing. learn her gaps and flawless block her strings into u2 full combo.
in mid range bait her normals to whiff punish her and at close range she stuggle cause of her lack of fast mid so a poke war is good againts her .
i would say dont let her play her game try to counter zone her if you can just to disturb her and try to get in her wake up game isnt that great too imo. Beware of her FB its one of the strongest if not the strongest fb in the game in term of damage and scaling but has limited range.
This.
Skarlet's arsenal of vein works in conjuction to push other characters into her zoning position, as you get closer to her she gets easier to deal with, but if she launches you her damage conversion goals its to send players back to fullscreen to mess with oppoent's patience while they get in the clock keeps tickening.
The key here is patience do not cruch under blood balls or jump over them, they take forever to start and you the key is to read when one is about to come out so you can counter it with another projectile or a move that bypass it, or better yet or advance before it comes out as much as possible then guard it, you won't win but the distance closing makes a lot of difference.
If you hold guard as she is launching the projectile, the second you decided to do anything and the projectile is already on screen and its a strong time consumer, and its very plus on block fullscreen, so if you block one she can fire another projectile or use tenctacle in case you try to move right after.
Midscreen its like Deathstroke said
Just be careful to not overextend or overeach when fighting her, since her mobility is excellent, her whiff punishing game on certain ranges is pretty good, and her KB are pretty easy to set up, specially the 310 damage throw, the B12 on whiff or Counter Hit, and the parry one, try not to get these setups to stack otherwise she is going to be very hard to deal with.
Her Fatal Blow has limited range but its a 13f armored mid, be careful how you approach when closer.
Never get cornered by her, Skarlet at the wall has a strong lockdown game due her range, and she has normals that can connect a free blood ball ãt +29 2hit combo when she is close enough and these sets up 50-50s.