How can I produce more variety of greeting cards?

Hi,
Basically you need creativity and innovation.  You can have it or you can hire someone that has it..... on top of it there are good techniques (e.g: S.C.A.M.P.E.R of "Po Word" [Provocative word] just 2 to mention).  It happend to me, more than once, that I hired proffesional people to get a creative idea and in fact I was the one to come with the final ideas..... (totally different from there early ideas).
Best regards,  

Dear,

you need to focus on creativity of greeting cards because now people looking for latest cards with animation, Flash, Good quotation on cards and much more. You can also visit some greeting cards sites like - 

http://www.123greetings.com/

http://www.americangreetings.com/

you can purchase softwares like MS Publisher to aid you in creating greeting cards