If you are interested in books, I really like The Law of Attraction and Ask and It Is Given by Jerry and Esther Hicks. They are easy to read and understand. The second book gives you a bunch of processes you can use to help you practice and become better at manifesting.
The premise of these books is simple: align with Source [I think of Source as universal energy] and live in joy. I have found the Hicks' writings to be invaluable for changing my mindset and becoming a more content, happier person.