In the Harry Potter book series Harry finds Snape's (Half-Blood Prince) old Potions journal. Not only does it help him with potions tremendously, (let's face it, Harry is a total science fluke) it also shows him new spells Snape created to probably use on James' band of hoodlums for picking on him, as well as other bullies.
First question: How does one make up their own spell? Any steps at all? (Remember references please.)
Second question: What other list of spells and information besides potions resides in Snape's old diary/ potions notebook? (Again please cite and reference.) Thank you!