As others said, later on in the game you get a couple of quests that enables you to go hunting for various crafting schematics so that you can craft so called 'Witcher gear'. These are the best armour sets in the game and each has different buffs, all depending on which 'School' you decide to pick. There's a couple of sets for every armour type. Wolf School gear is seen as the best all round, medium armour that gives moderate damage and defense buffs, as well some buffs to your signs. Basically the Jack of All trades armour in the game.
But honestly, I wouldn't be too worried about trying to get the best stats and items in the game. Just take it easy and enjoy the story, the lore and the characters.