I've identified the segments and saved them but need some images or graphics. Does anyone here have any experience doing that?
Is there a preferred format to use?
unless you have a special demographic, the majority of your users will see your ad via the mobile stream.
in the ad manager, when it asks you to pick Graphics it gives you a suggested size. That suggested size as what you should use. They will fit the mobile advertisement ratio best will giving high quality.
do not use stock art unless you want to have nobody look at your advertisement. Keep the texts to a minimum on the pictures.
Unique picture.
Short catching phrases for the title and the subtext
add a call to action button to link over to your website or other Facebook page with further details.
Consider making two ads and using Facebook's a:b testing. That is in the ad manager when you're setting things up. From there you will know which one is more effective and can't we cure strategy in the future.
Follow the data! if something is working better than another advertisement, drop the other ads and quit wasting money on them.