It's better to check current ANN posts and the post creator ranks. Note down the designs you like and dig into the Html codes. Mostly, well known forum moderators and high ranked users start the ANN posts, so if you need help, you can contact them. Also, check the translators on ANN posts. On local boards, translators also posts for local announcements...
Go to "Help" in top navigation bar. Then click on "Posting" and then scroll down to "SMF Bulletin Board Code".
A direct link to that page is here : https://bitcointalk.org/index.php?action=help;page=post#bbcref