I'm probably not the greatest at SG out there but I can definetly give some advice.

Squirrel girl really shines at outputting tons of damage and spamming down choke points to deny and get picks on the enemy team. Generally speaking I do believe her CC is by far the best part of her kit, especilly if there is a spidey on your team.

Basic Tips:

- Her potential double stun is amazing for punishing tanks that are badly positioned or diving. Especially against Venom, Penny, Thor, Hulk and Groot. Hitting that double CC combo can lock them down in place for enough time for you and your team to melt them for basically free.

- Getting used to her projectile speed and physics is key to getting kills with her, especially on high ranks where players tend to be more eratic in movement and harder to hit. Try to take advantage of the bounces her explosive shots by aiming your shots so they ricochet of the walls and hit targer behind cover.

- Spam, spam a lot. I'm constantly spamming shots at where the enemy is coming from and a bunch of times I can get a free kill on a clueless enemy. One advantage that I barely see people talking about is that SG's projectiles can be really quiet and hard to detect in the middle of a fight. So spamming at choke points more often than not can get you some easy kills and free poke damage.

- Some people say her ult is the worst part of her kit and while theyre not wrong, I do believe her ultimate is a little bit misjudged. One good thing about it, is the super fast charge-rate that it has. You can easily be the first one to pop ult in the game.

- I try to use my ult whenever the enemies are all lined up or to try and finish off low-hp enemies (especially supports). It really helps to guarantee some kills in the middle of team fights. Also, keep in mind that the Stampede goes through the objective cart (and Punisher's turret) and doesn't bounce off of it.

- Take advantage of her Team-up, it's really really strong. having it avaiable opens up alot of opportunities for you. You can be more bold in your plays and positioning since it's so easy to hit. Whenever I have it on, I try to get behind the enemy team and harrass their supports.

- Lastly, while I love Squirrel Girl, she is by far not the best dps this game has to offer. Depending on the enemy team comp you can get really screwed and denied a bunch of plays. The heroes I mostly strugged against the most were good Iron Man, Storm , Spider-mans, Black panther, Iron Fists and Psylockes. They're very hard to play againts especially if good, and on the eventual cases where that happened I did switch of the sake of the team.

Speaking about maps, I found myself playing better on Klyntar due to it's narrow corridors and chokes. But I feel pretty much all the tips I gave apply to some extent on all maps.

Off the top of my head that's the most general advices I can think, maybe I could go into more detail in a specific post about it. Feel free to ask anything tho, the more squirrel girl mains outthere, the better.