Create a timeline of your research topic. The Information Age has conditioned us to search using keywords. Many historical documents online are not text-searchable, but are often organized by date. If you know a date range, you can browse documents for relevant information.
Follow the clues left by others before you and expand on their research. Look at authors' reference lists to discover publications or collections you may not have considered.
If at first you don't succeed, try again.Not every lead is successful, and you may meet several dead ends during your search. Try thinking about your search in a new way with different keywords. Sometimes broadening or narrowing your original topic opens up more possibilities.
Remember you are part of a community. Face to face interaction still works! Consulting your local librarians, meeting with the local historical society, or visiting local museums is a great way to find people who can share their expertise and knowledge.