Productive research involves various search strategies and a wide range of search engines and databases.
Researching is like building the foundation of a house. It forms your understanding of your topic and helps you form a strong argument for your paper. Without a strong foundation (understanding and argument) your house will collapse (your project will not score well).
Search strategies will evolve as you understand your topic better and your vocabulary around the topic develops.
Research is an open-ended exploration.
Be persistent - try different combinations of search terms and search strategies.
Think quality over quantity.