Early game you want to roam very much. She is not the best laner, but a succesful combo and assist from one of your team members you can secure the kill. Especially at level 4, since you have Envenom.
In teamfight, you don't want to jump in with Maelstrom in the middle of it. Scout, and cath their Ranged Assassin or Specialist. When you are getting low, cast the Blood for Blood on the enemy tank, since he has the biggest health pool, and 15% of a 5000 health is more for you than 15% of a 3000 health. If you are prioritised, just use sprint and get out of there!