I need to know how to make a quick decision on Simple things.

Like the question, i need to know how to make a decision on simple tasks such as buying a t-shirt, what to order at Chick-fil-a. You know and i get all, Undecisive, and start calling people what do you think? I just can't make Snappy Decisions. I begin like, do i need it?, Why do i need it? I could not buy it and save money. I dont think i have anything that matches it. Or things like that. I doubt my confidence. Please help thanks.