MongoDB querying includes filtering with find and operators like $gt, using projections to limit fields, combining conditions with $or and $and, sorting results by fields, implementing pagination with skip and limit, and advanced data processing using the aggregation framework for grouping and calculations.

Efficient document querying in MongoDB utilizes the find() method with filters for targeted results. Employ logical operators like $and and $or for complex queries. Index creation enhances performance, while the aggregation framework processes data through pipelines for insightful analysis. Optimize queries with strategic indexing and the explain() method.