This chapter discusses the insights developed for designing scheduling algorithms according to three design projects where algorithms have been developed. The choice of applications covers a broad spectrum. The methods used are from three different fields, namely combinatorial optimization, genetic (evolutionary) algorithms, and mathematical optimization. The application areas differ also in terms of the role of a human user of the algorithm. The three application areas are: 1. Decision support for shunting yard scheduling using a network flow heuristic; 2. An evolutionary multi-objective decision tool for job-shop scheduling; 3. Group sequencing: a predictive-reactive scheduling method for job-shop scheduling.