I would do a bit extra. What that is depends on what your task is and team culture is, and I wouldn't go overboard, but I think that doing 10% more will make you stand out. Try to ascertain the team culture and work with it, not against it. If the team is all about shipping, think of ways to ship quicker. If the team is in a bit of an operational mess, think about documenting processes or writing scripts.

What are examples of this?

   * if you are given an operational task that isn't well documented, document it.
   * if you are given a task that isn't documented at all, document it some
   * add a few more tests than you might normally. Or, if there is no testing framework, discuss why not and see if you can add one.
   * read code and create draft design docs

A big one that would be helpful to every team I've ever joined is to take notes about onboarding and either create a doc/scripts to help folks get up to speed or improve existing doc/scripts.

Of course, notice what the team's feedback is and adjust your actions if it is negative. You want to come across as helpful, not as a 'know it all'. I've definitely been too eager sometimes and come across the wrong way.

Also, you could ask your manager or other team members what they wish the team was doing and see if it is something you could help with.