The single container loading problem consists of a container that has to be filled with a set of boxes. The objective of the problem is to maximize the total volume of the loaded boxes. For solving the problem, constructive approaches are the most successful. A key element of these approaches is related to the selection of the box to load next. In this work, we propose a new evaluation function for ranking boxes. Our function rewards boxes that fit well in the container, taking into account the previously placed ones. To construct a more robust function, we consider some other well-known evaluation criteria such as the volume of the block and the estimated wasted volume in the free space of the container. Our approach shows promising results when compared with other state-of-the-art algorithms on a set of 1600 well-known benchmark instances.