General Index Strategies

I’m reading Pro MySQL, and just found those guidelines on indexing which look so helpful

• Analyze WHERE, ON, GROUP BY, and ORDER BY clauses
• Minimize the size of indexed fields
• Pick fields with high data selectivity
• Clustering key choice is important
• Consider indexing multiple fields if a covering index would occur
• Make sure column types match on join conditions
• Ensure an index can be used
• Keep index statistics current with the ANALYZE TABLE command
• Profile your queries

i know each one of these guidlines is a big subject on its own, but i think thats your job to search about it