Okay, so, the best way to get high friendship is to make sure that you visit the cafe's around the city. You can visit the same cafe over and over again as many times as you like, and each visit costs around 700 poke-dollars, and around 4 to 7 visits actually maxes out visits. So the cost to max out friendship in this way could cost around 4,900 buckarronies, but its a bang for your buck, its a lot faster than battling and running around in circles while the pokemon has a soothe bell lol. So just keep visiting those cafe's, you're on the right track!