How Do I Make My Clothes Shrink In The Wash?
The problem with shrinking clothes on purpose is the shrinkage you will achieve is random and most of the clothes that do shrink will just stretch back out over time as you wear them. As you said hot water is the only temperature that really does this and then you’ll be facing a problem with the fading of colours even with reduced temperatures. If the garment tag states cold water, it probably does so so you won’t fade it washing it in the wrong temperature. Your safest bet to prevent ruining your clothes is just to take them to a tailor or dressmaker and get them altered.