Currently, several thousands of scientists from all over the world are preparing for the first beam collisions at the Large Hadron Collider (LHC). This accelerator at the European Center for Nuclear Research (CERN) in Geneva/Switzerland will provide the opportunity to make precision measurements of top quark properties and eventually to discover the last fundamental particle proposed by the Standard Model (SM) of particle physics: the Higgs particle. In order to do so, the detectors, for example ATLAS, have to work reliably and be well understood, and systematic uncertainties in the event reconstruction or in the physics modelling must be reduced as much as possible.In this thesis contributions to three fields were made: hardware production, installation and commissioning for the ATLAS pixel detector (Chapter 4), data calibration (Chapter 6), and physics analysis preparation for first data (Chapter 7). Each of these three fields is important for or strongly related to top quark physics.