We'll talk about the don'ts first. Some of these seem petty, but they add up. It's amazing how fast a person can shut down over one little fact. (Please keep in mind that I have written in the perspective of a male attempting to get a female partner to play. This is the only situation I have been faced with. If you are a female trying to get a male to play or a male getting a male to play, or whatever other combination you can come up with, then tell me and I will rewrite it without being gender-specific. Until then, you will just have to put up with it.)
Dont's
Don't EVER exclude your S/O from any computer activity. Exclusion breeds resentment. Don't ever say "It's a guy thing." Or, "These guys are pretty good and you wouldn't hold up." If she wants to play, by all means, let her! After all, that's the whole goal. Dying can be fun, too, if approached right. My husband has been playing FPS's since Wolfenstein. I had just as much fun dying as he did killing me. (Hm, I wonder how he feels about me killing him now. I know I enjoy it!)
Don't EVER stick your S/O with the kids or other work so you can play. Bad, bad, bad. Again we have the resentment factor here. I know I sure as hell hate it when Frogmaster gets to play while I have to take care of the baby (it makes me feel so, so, 50's domestic-like). If you can, do something else until she is free.
Don't push. Always ask if she wants to play, but take "No!" for an answer. She will when she is ready. If you push she is likely to give in just to get you off her back, but then probably won't enjoy it very much. No one wants to do anything they feel forced to do.
Don't give up on it, though. My husband kept after me for two and a half years to get me to play. That's a lot of patience, but well worth it. He made me realize how important it was to him that I try gaming. It was more time we got to spend together. Besides, do you think I'd let him go to all night gaming sessions without me? Ha!
Don't throw her on-line and expect her to enjoy getting killed by a bunch of mouthy 15 year-olds. Nobody likes that. Let her start off in a comfortable way. I've listed a few below.
And finally, please, don't get angry with her if she's not picking it up right away. If she gets frustrated - fine, everyone does when trying to learn a new game. But don't get snippy. You snap at her once and it could blow the whole thing. I know I get real testy when I try something ten times in a row and just keep dying. If my husband would have raised his voice one time while trying to teach me these games, it would have killed it for me (and then for him!) completely.
Now that you know some of the things NOT to do, here's a list of things that you SHOULD do.
If your S/O asks you to shut down the computer, DO IT! Don't make her feel like you would rather spend your time on-line than with her. The resentment invariably goes to the wrong place. (e.g. the computer instead of you, where it belongs.) I cannot stress this one enough. I had an ex that killed my interest in computers for years because his time on them was SO IMPORTANT (please note the heavy sarcastic childish tone of voice here). Nobody wants to be brought down to the level of competing against an inanimate object for attention. It's demeaning and you'll regret it.
Let her try different games. Don't let her give up if she doesn't like the first game you throw at her. Try different genres until you find something that clicks. Once she finds an enjoyable game, she might be more open minded to other ones. Once I started playing X-Wing vs. Tie Fighter (left handed mind you), I decided to give C&C a chance, then Diablo, then Quake II. Now, I'll jump on just about any demo out there!
Let her have the computer for (insert favorite diety here)'s sake! She can't learn if you are on it the whole time she is home. I made my husband build me one because I couldn't get any time on his and my daughter's wouldn't play half the games. If you can't afford that, make sure she has plenty of opportunity to get in the driver's seat.
Get a group of people she is comfortable with and have a mini-LAN to get her started. It's always easier when you are playing against people you can joke around with. Go easy on the newbie. Don't kill her too often, but enough to get the point across. Tease/congratulate her when she gets a kill. You can start her off with single-player to get the controls down, but then get her to play against people. You can't joke with AI; they have no sense of humor.
Set up LAN parties for your house when you know that she has nothing else to do. When I was pregnant and needed wrist surgery (thus, I couldn't drive anywhere) my husband and my brother and a few friends disappeared into the basement every Saturday night with their computers. I was left upstairs, alone, with nothing but the TV. After a while, I gave in and joined them for a dose of sanity and socialization. Now they can't get rid of me!
If you find a game that she is good at, don't begrudge her for it. Play it as often as you can. When I first started playing, it was against people who had months (years in some cases) of practice over me. I always finished last in EVERY game we played. That can get a person down after awhile. Imagine my delight when we put together Frog Pak 4 and I was able to kick ass in a few maps every time I played them. Poor Frogmaster, I made him play them again and again and again...
Try doing something that she gets into. Hobbies are always more fun when you share. After all, it's more time spent together. Besides, she'll be more into learning something you like. You know, what's good for the goose type of thing.
If she still doesn't want to try, then you just have to accept the fact that computer games might not be the thing for her. Believe it or not, people like that do exist out there. But, you never know. People change over the years and might be more open to things later on.
Legal notice - I refuse to be held responsible for any bad Karma that may have been generated in your lifetime! If something happens to you and you think you want to blame me because of this advice, grow up. You and only you are responsible for what happens in your life, not me, not the people who built the computer, not the ISP that hosts the web page. Get over it and get on with life. Quit yer whining, etc., etc. Deal.
Any suggestions/comments/things that worked for you? Send them in!