I do a monthly newsletter and yes, I do worry about content so I work at least two months ahead (Dec and Jan newsletters about ready to go, just need finishing touches) which takes the pressure off.
Content - well, I try and have one main article then include a little bit about what's been discussed on my blog over the last month, links to two articles that may be of interest to my audience and any information about new services I may be offering.
This was my last one
http://mim.io/bea06
HTH
