How do keep clutter from growing? Remember minimizing clutter is not to just get rid of stuff, it helps create opportunities for what you really want. This is a constant battle, but here is an example slash true story. You get a new great t-shirt that you really dig. There is an opportunity to look at one of your existing shirts in your wardrobe. It can be difficult especially if you have a shirt that you are sentimental about. I will place that shirt in the donation (or hand-me-down queue) queue and solve two things. Preventing my stuff from expanding and giving to someone who needs a shirt. Sometimes in my mind, I will think I want to wear that shirt. I get to the closet and realized that I gave it away.
You think I would miss the shirt? The truth is I don't. My hope is that it has a home or has been re-purposed in some valuable way. It's an awesome feeling.
Try it next time you buy something. You will begin to realize you only have the things you want and things you love!