How to keep rugs from shifting?

In my new apartment, I will be having some porcelain tiles in the main living area, with a large persian-style rug, which will be underneath 2 large couches and a coffee table. I have heard from numerous people that rugs move a LOT, even when placed on carpet, even when using the Velcro or sticky thingos on their bottom, and even when placed under furniture.

Help? lol

I think you've been lead down the garden path. The rubber anti slip things feet and partly anchored by couches will be fine

lol. I'm not quite sure what was happening, but at my parents' house, their nice rug which was under a very heavy coffee table and on top of plush pile carpet, had the anti-slip rubber things on the bottom, and STILL I would literally watch as the rug AND the coffee table moved along the carpet over the course of a few hours of normal living.

Rugs on carpets.... Pfft.

Carpets have a pile which when compressed down moves. It's this movement that moves the rug. The higher the pile the more movement. Every time you step on the rug it compresses the pile underneath and moves it, moving the rug...every... Time... You...step... On...it. Lol. You will not fix this problem. Unless you can change the laws of physics. You can minimise the issue somewhat but you'll always be adjusting rugs on carpet. Hard surfaces are the easiest to control rug slip on. Forget the rug on the carpet is my advice. The rubber feet or scatter mats (a product) will help you with slip on a hard surface.