Padding and Margin padding and layout_margin are two very similar attributes. Both determine the space around a View. The difference is that padding determines space within the boundaries of the view, and layout_margin determines the space outside the boundaries of the view. Width and Height Some of the most important properties are the width property and height property - those must be defined for every view. Remember that all views occupy a rectangular area on the screen - the width and height are the width and height of that area. You can define this in pixels, or better yet dp (stands for density-independent pixels): android:layout_width="200dp" android:layout_height="300dp" For the sake of having a layout be responsive and adjust to different devices, two common values are not numbers at all, but wrap_content and match_parent used as shown here: android:layout_width="wrap_content" android:layout_height="match_parent"