A compliment sandwich is disapproval smashed in-between two compliments. Really it's just sugar coated criticism, but it does help to lighten the blow.
A shameless plug is when you knowingly promote yourself, business, or product, without shame or reservation. You can use Infosnacks for shameless plugs!
Writer's Block is when someone, typically an author, is unable to start or continue their writing. This term is often applied to any creative activity.