Definition of Done
The Definition of Done is used for creating a shared understanding of when a Product Backlog item can be considered done.
Definition of Ready
Definition of Ready serves as a precondition for an item from Product Backlog before entering a Sprint/ Iteration backlog to prevent problems before it starts.
Lightweight framework - complex problems poster. Scrum is a framework not only for software development guiding the increment creation process, while offering enough freedom.
SMART Tasks / Goals
Effective tasks are SMART poster. SMART acronym offers parameters to use when creating tasks.
INVEST in good User Stories poster. INVEST acronym provides a guidance on how to write user stories the way they are supposed to be written.