I don't know all 12, but I can tell you some.
1. Shade the side of the line that satisfies the inequality.
2. If the inequality sign has an "or equal to" line under it, make the line on the graph connected.
3. If the inequality sign does not have an "or equal to" line under it, make the line on the graph dashed.
4. Isolate y (or the variable that is being used), and keep it on the left side of the inequality.