Reason for Protection Spell
Spells can be used for offensive reasons and it is often these spells that are the most publicised and often the most impressive. However, magic can equally be used for protection purposes and to defend yourself. Often these spells are more complex and require a higher level of concentration than those used for offense, but they are ultimately more rewarding. With a protection spell, you are not just limited to helping yourself. The powers of a protection spell can be pushed out in order to add a level of protection to anyone else of your choosing, which can be particularly useful if you wish to add a spell to protect your house and everyone in it.
Identify what you want to be protected from
Until you know what it is that you want to protect yourself from, there is no way of knowing which spell you need to cast to protect yourself from it. Mental threats, black magic, or emotional trauma require a different kind of protection spell to physical threats.