Non-pharmacological interventions have the potential to reduce cognitive decline and to improve psychosocial aspects in mild cognitive impairment and Alzheimer's dementia, and the absence of side effects makes them a favorable option also for preventive strategies. We provide an overview on recent studies involving cognitive training and reminiscence, stimulating and challenging experiences such as visual art and music, physical activities, and electromagnetic stimulation. We review findings on neuroplasticity in the aging brain and their relevance for cognitive improvement in patients with neurodegenerative diseases. We discuss cognitive reserve and possible mechanisms that drive neuroplasticity and new learning. Finally, we identify promising avenues for future intervention strategies and research, such as combinations of cognitive and pharmaceutical interventions, and individual strategies adapted to the disease stage and tailored to the needs, predispositions and preferences of patients.