Should I bother with tax deductions? What are they?

First, I need to explain that I’ve already heard the definition of a tax deduction- "A reduction of total income before the amount of income tax payable is calculated." (So please don’t reply with just a simple definition) What I need to know is how that affects my return. I’ve asked a lot of people and no one can give me a clear answer. I have student loans out and I need to know how (and how much) it would benefit me to claim a deduction based on the interest I paid on them last year. Will the deductions increase the amount of my return or are deductions only necessary if I think I will owe the IRS money? I’m really confused to please answer in simple layman’s terms. Pleaaaaaaaaaase, for my sanity- only answer if you really know what you’re talking about! Thanks