For me low magic is just a game where you aren't tripping over +1 sword that you just add to you bag holding full of +1 swords already and take to nearest town sell it all and buy something better.
So it doesn't have to be no magic just less of it. I've run quite a few APs and by book 4 you usually are tripping over useless magic items. So when I go low magic I make so this isn't the case. If I need a higher level bad guy in armor to have higher AC he has a oil of magic vestment. After the fight the breast plate is just a breast plate but during the fight it might be a +5 breast plate. The players will have magic items. They would gain them through quests as there wouldn't be magic shops but potions and scrolls would be avialable. Casters would rare though and you'd have to track them down. That's what low magic is to me.