The first thing that you want to do is maintain a happy household if you're family member. Trying to play a mean game of Super Mario Tetris or Halo 2 can be impossible with kids running around the house and screaming bloody murder. You won't be able to enjoy the latest role-playing game when the wife's nagging you about bills or undone chores too. Keep a happy home, keep a happy marriage, and your time spent playing video games is heaven away from heaven.
It's no secret that some games require as much concentration and focus as when studying for a calculus exam - and there's nothing more frustrating than when you can't figure out how to get through to "the next level" of a game. This is no time to be distracted and if home life isn't what it could be, you'll never be able to concentrate on your game. Strive to make home a place to unwind first - then work on enjoying your games.
You can next dedicate a place in your home as your exclusive game room. This will not only emphasis the importance that gaming is to you (and to your family members), it will also become conducive to the mentality that you need to play a fun and relaxing (albeit, serious game). Budget permitting, decorate the room with all the amenities that you want. You could add a recliner (or two for your friends), a small stand to hold snacks, a bookcase for your games, and you could even add a small refrigerator and microwave (just in case). Your intent here is to declare the space as yours and that it serves only one purpose: pure gaming pleasure.
What you're after is a place that's completely and totally pleasing to you, both aesthetically and functionally so that you'll enjoy your time there.
With your own space dedicated to gaming, you'll want to do what's necessary to maintain it and keep it in a condition that's inviting not only for yourself, but for others as well. Keep your equipment and games clean. Take care to keep wires from tangling and organize your magazine subscriptions, books, or Internet cheatsheet printouts. Maintenance is a task that doesn't have to burden you as long as you make a daily routine of it. The advantages of keeping a regular maintenance schedule shows that this space is important to you and that you have a right to keep it that way.
But take special care not to alienate yourself from the rest of your family. We all can have a favorite hobby and we can even dedicate a special area of the home to that hobby. However it's extremely important to regard this place as a haven - not a hide out. It's not an area to hide from the kids, it's not a place to shun home responsibilities, and it's not a place to live. If this special space is approached in the latter manner, you'll soon discover it as a place of resentment, uncontrollable habit, or even depression. Be careful, schedule time with the family, and enter your playroom at appropriate times. Cooperation from others will then come naturally.