Never repeat a word more than 3 times in your keywords.
You can have more than 6 keywords but generally the fewer words the
better off you are...
Repeat the keywords as many times as you feel like in your content,
however do not spam it i.e. don't put them in loads and loads to
delibaratly up the number... if you have a lot of thext you should
have the keywords there alot as well (shows your sticking to the
Try yo use the keywords in the title and description too...
Hope this helps