You claim skins and enter into raffle contests by completing Quests on http://live.gearsofwar.com.
In order to complete these Quests, you must be logged into and watching on the official Gears Esports live site – http://live.gearsofwar.com (On ANY channel! And don't worry, you can still use Mixer, MLG and Twitch chats!). Once you arrive at the page, all you need to do is sign in using your Xbox Live Gamertag by clicking “Log In” in the top right corner. From there, simply click on the “Quests” tab to check out the different Quests, then follow the steps listed for each Quest, and click “Submit Entry” once you’ve completed the objectives. Skins should be entitled to your account within minutes, while raffle winners will be contacted by a Gears Esports team member through Xbox Live (‘Gears Esports’ Gamertag) within a week.
(Click here for more information on how to sign up and complete quests.)