Projects succeed or fail because of the people involved, regardless of the processes or methodology used.
The way a team works together and feels about itself can have an effect on the outcome as big as or bigger than individual members' characteristics.
Testers help facilitate communication among members of the development and customer teams.
Do the simplest tests you can to verify that customer requirements are met.
Don't work alone partner with other team members for tasks such as test automation, and ask for help as needed.
Be persistent, and keep your perspective.