The simplest is a 3-card, left-to-right line for past influence, present situation, future awareness. Word your inquiry somewhat vaguely as "what should I know about X to protect myself?" then interpret the cards as replies to that question within the position they occupy.
Your post title mentioned a protection spell. Good gad there's thousands. Method is totally flexible. Consider what you've got on-hand to work with. Get your intention clear in your gut. Yes, gut-feeling, not just head space. For simplicity you should be able to adapt a candle. And you can charge any piece of daily-worn jewelry along with it. Setting your intent in any item is the same procedure. Keep in mind that a piece of jewelry isn't a Kevlon vest & can't stand up & "protect" anything. When bespelled it holds the intention of protection. What it will do is alert the mind of the wearer to potential harm so they can take simple steps to protect themselves. If you believe in a guardian spirit then request their assistance to "ride shot gun" for you.
Instructions for a lengthy list of spells that can be adapted to any need are here:
http://everythingunderthemoon.net/forum ... 36682.html