Here, we summarized three general methodologies for controlling molecular aggregation, which can help guide the development of new functional aggregate materials. The first strategy is molecular modification before aggregation, where properties like size, shape, and substituents are altered to influence intermolecular interactions during aggregation. The second involves manipulating the aggregation process through solvent induction, temperature control, and kinetics vs thermodynamics. The third uses post-processing methods like photo-and mechano-induction to modify the properties of the final aggregate material. Due to the experimental easiness, the first and third have gradually been discovered and investigated. On the other hand, the second is the most challenging, although generalizable, as dynamic processes are naturally more complex to perceive and control.