Developing a keyword strategy for effective enterprise-level SEM involves conducting keyword research using tools like Semrush, WordStream, SE Ranking, and Ahrefs. Identify primary and secondary keywords that target potential customers at different stages of their buying journey. Primary keywords should be high-volume, competitive keywords, while secondary keywords should be long-tail and low-competition. Incorporate these target keywords into important elements of landing pages, such as title tags, description tags, H1 tags, and paragraph content to improve website positioning in SERPs.