In addition to the below resources, be sure to check out the OWL Writing Lab icon on the home page. This will take you to Purdue's Online Writing Lab which possesses a ton of useful information on all things writing.
What are sources and how to find them
What are citations and how to cite
Grammarly
Grammarly can help you become a better writer on the fly!
Hemingway
Hemingway Editor can help you become an even better writer!