I do drip acclimation. If the betta comes in a cup, I move him to a baggie and put it in a bucket to keep it upright. Then I take a piece of airline tubing and kink it so that it drips into the bag. I add twice as much tank water as what the fish came with. I think this method works best when the pH of my tank is different from the store's. It takes a while. I check every 5 minutes to see how the fish is doing.