Ok I will see if I can help you here. It may be a good idea to do a monogram first so you have that on all your stuff. It ties it all together.
To make the save the date I would recommend doing just a simple magnet or postcard sized envelope. Here is a helpful site Save The Date Magnets, Wedding Invitations, Postcards for Weddings, Magnetic Favors
I sent my STD's with out much thought but have put a lot of thought into my invites and I am happy I did. Let me know if you need anymore help and have fun!!