Accurate modelling of flows with non-spherical particles is important for a wide range of industrial applications. State-of-the-art CFD software fails to include crucial information on exact shape and orientation of the particles, resulting in less accurate modelling of highly non-spherical objects such as flat plates. An extensive study of the forces and torques on a plate, reveals the existing modelling framework for flat plates in free fall to be insufficient to describe the actual trajectories using an Euler-Lagrange approach. Through numerous CFD simulations, new correlations are proposed for rotational lift, rotational drag, and centre of pressure location, resulting in a model able to predict the trajectories with high accuracy. A comparison to a regime map found in literature suggests the model to be general applicable to a wide range of plates, and therefore this work has led to a significant improvement of the existing modelling framework for flat plates in free fall.