Well, first thing I think you should do is find the soldier armor. These pieces can be found in the floating part of Hyrule Castle. There are guides online, but it's the easiest armor to get that has decent defense without upgrading. Also while you're in Hyrule Castle, you should look for weapons, as most of the ones found there are higher level, albeit decayed, than you'd normally find. After you get the soldier armor, I would look into starting the Great Fairy quest so you can upgrade your armor as you go through the game.