We present a constructive approach to torsion-free gradings of Lie algebras. Our main result is the computation of a maximal grading. Given a Lie algebra, using its maximal grading we enumerate all of its torsion-free gradings as well as its positive gradings. As applications, we classify gradings in low dimension, we consider the enumeration of Heintze groups, and we give methods to find bounds for non-vanishing ℓ q,p cohomology. Contents 1. Introduction 1.1. Overview 1.2. Main results 1.3. Structure of the paper 2. Gradings 2.1. Gradings and equivalences 2.2. Universal gradings 2.3. Gradings induced by tori 2.4. Maximal gradings 2.5. Enumeration of torsion-free gradings 3. Constructions 3.1. Stratifications 3.2. Positive gradings 3.3. Maximal gradings 4. Applications 4.1. Structure from maximal gradings 4.2. Classification of gradings in low dimension 4.3. Enumerating Heintze groups 4.4. Bounds for non-vanishing ℓ q,p cohomology Appendix A. Existence of a positive realization References