Optimizing queries and indexes is a key component of handling large datasets in ORM code. Queries are commands used to retrieve or manipulate data from the database, while indexes are structures that create shortcuts to the data. When optimizing your queries and indexes, you should apply general principles such as using filters and conditions to limit the amount of data fetched or updated, joining and associating multiple tables or entities, projecting and selecting specific fields or attributes, aggregating and grouping to summarize or categorize data, sorting and ordering to arrange data in a certain way, caching and caching strategies to store data for faster access, explain and analyze tools to examine the execution plan and performance of queries, appropriate data types and constraints to ensure validity and efficiency of your data, indexes to create fast paths based on fields or attributes used for sorting or filtering, index types and options to optimize index performance and storage based on the data characteristics and query patterns.