If you go on any page, there’s a link to the forums below your custom cat (specifically below your friend requests) and then you just scroll down to Raffles & Giveaways. Then, you can go on any thread, read the main post for the rules, and participate in the giveaways and raffles. Since a lot of them are specifically for users who joined for End of Beta, there’s not always that many people participating and you can get a lot of goodies.