1) PokéStops Refresh Often
Besides going Pokemon hunting, the next thing you should be looking out for are PokéStops. If you happen to see a few nearby your current location, stick around and replenish your supplies of Poké Balls and other goodies. A PokéStop changes its colour from blue to purple once you have interacted with it and after 5 minutes or so (timing can vary), it will return back to blue where you can once again stock up on your necessary items.
TIP: You also get 50 XP per spin of each PokéStop, which is useful if you’re surrounded by all these PokéStops but have no Pokémon are nearby. Even if your bag is full, you should still swipe it anyway.