When I am looking up a specific topic on LDS.org, one of the first places I go is to the Scriptures and Study main menu. Under the Scriptures sub-menu is Study Helps. There I can find scriptures on a certain subject in the Topical Guide, and in the Guide to the Scriptures. The Bible Dictionary is also a part of the Study Helps and has definitions, historical background, short biographies, and other information to help us understand the scriptures.
One of my favorite places on LDS.org is Gospel Topics. It is in the Scriptures and Study menu under the Learn More sub-menu.
Gospel Topics is organized alphabetically. Just click on the first letter of the topic you want, for instance I choose "Charity" and clicked on the C, then from the topics starting with C, I clicked on "Charity". This link takes me to a page where there is a definition of Charity, Additional Information, Scripture References, Prophetic Teachings (mainly General Conference Talks on that topic), and Additional Study Materials (primarily links to material in Church manuals on that topic).
When you really want to do in depth study on a topic, check out the Gospel Topics essays. Just go to Gospel Topics and click on the blue Explore the essays link on the right side on the page. Then click on any of the blue topics links on the right of the page. This will take you to that specific essay such as "Are Mormon's Christian?" Be sure and click on the blue Seek learning by study and also by faith link on the Gospel Topics Essays page for more study helps and links.
For help with understanding and answering questions about Religious Freedom go to https://www.lds.org/religious-freedom?lang=eng. This site is under the Scriptures and Study menu.
So, if you are looking for material on a certain topic to help you write a talk, or you just want to enlarge your Gospel understanding, check out the Study Helps and Gospel Topics under the Scriptures and Study main menu.
Here is a great place to help you prepare a talk. https://www.lds.org/service/teaching-the-gospel/prepare-a-talk?lang=eng