What to do when you win a giveaway.

Yup. 7 day window :)

see your mail or wait - maybe add in steam and give a key or gift

Wait of the email or steam friend request.

Thank them when you get your game you won, and mark it as received when you activated it to your account.

or u can add the person on steam and tell him u won his gift away on here.

You can wait for the email, looking also in your spam folder, or for the gifter to add you on Steam. The gifter has 7 days to complete the transaction with you.

If after a couple of days you didn't get anything, you can also add the gifter. Sometimes emails just get lost or end up in the spam folder.

Once you received the game, just mark it as received on the website.

I have a question too. (I did read the FAQ!) I want to enter a collection giveaway and it states "If you already own 1 or 2 of the games you can still enter to the giveaway". I own one, so I can enter. But what do I do with they one I already have when I win? I can not re-gift or anything according to the FAQ, so do I keep this key unused, just ignore it? (I have not won yet, probbly won't, but just wondering.) Thanks in advance for any answers. :)

Read the FAQ please

I'm doing my victory dance. Like this one.

Wait for invite/email.

Then you dance.

Personally I commence the cossack dance of victory

Immediately create a giveaway.
Not a giveaway of the game you just won, of course...;)

Just activate the game and look at it forever!

strip down to just my socks and masturbate furiously

yes wait for email or friend request :)

i sacrifice a virgin, so the SG Gods wont be angry at me.