Industrial Engineering is essentially a toolkit of techniques and skills -- which can be applied virtually in every industry/company.
So, from a technique standpoint, one can start with,
*Statistics
*Value Stream Mapping / Process Mapping
*Lean Management / Six Sigma
*Productivity / Ergonomics
Requirements
*Good math skills
*Strong time management skills
*Mechanical aptitude
*Good common sense
*A strong desire for organization and efficiency
*Excellent communication/salesmanship
*Creative problem solving
*Quantitative skills
*Technical competency
*Continuous drive for improvement
*Resourcefulness
*Listening skills
*Negotiation skills
*Diplomacy
*Patience
*Ability to adapt to many environments, wear many hats and *interact with a diverse group of individuals
*Inquisitive mind
*Continuous desire to learn
*Leadership skills
*Ethics
*Passion for improvement