All this discussion presupposes that your guitar is tuneable!

Straight neck
Decent action
Non-dead strings

are a prerequisite.

By the way, Isabel, in your original post you asked if there's a way to "secure" the tuners. If they are decent quality tuners, there is an adjustment screw on the end of each peg which allows you to do just that. Just take a small screwdriver and tighten the screw until the peg gives you some resistance when you turn it. If it gives you no resistance and immediately spins a quarter-turn when you touch it, that's the problem right there, and just as easily solved.


W-O