Before you can tag a person or a Facebook Page in your status. Make sure that you already LIKED the page or if your tagging a person, make sure that you are friend with him/her.
First, go to your WALL and write normally. To tag a person or a Facebook Page you must put the" @ " sign first and put the first few letters of the Page your tagging, just like above. You will notice that a drop down menu will come out. Click the one that you want to be tagged.
You will noticed that it will turn blue, that means you already tagged the person or the page. As far I know you can include up to six (6) tags in a single Facebook status.
If you are joining a contest, they require you to show your status to everyone. You can check your current settings if you mouse-over on the padlock icon. Just like in the photo above, it says "Friends Only" so non-friends cannot see your post. Tagging a Fan Page will not make your status public.
To make your status public, click the padlock icon and check "Everyone" and that's it. Click SHARE and your post can be viewed by anyone, even non-friends.