Like a Dragon: Infinite Wealth

Raids can be found all over Hawaii – you'll see enemies surrounded by a coloured forcefield, nd you can interact with them to do battle. You can see the level of your enemy before committing to the fight, so, for an easy life, only challenge lower level foes. This will also bag a guaranteed win, so you can chalk up 20 much faster. To find raids quickly, consult your map – they're marked as diamonds, each pertaining to their specific type. Make sure they're active, too, before you travel to them.