There is a lot of talk about drip acclimation on here and for someone new to some of this you may not know what it involves and how easy it is.
First off, drip acclimation is a way to slowly
get the fish that will inhabit your tank to get accustomed to your water. A severe ph shift from the water they came from to your water is enough to kill some fish and is known as ph shock. Since I have been using this method my losses a day or two after the fish store have decreased by probably close to 80-90% and the fish doesn't go to one spot and sit for a few days. They are very active immediately - usually. Shyness is inherit with some fish.
Anyway, I thought I would explain with pics what is involved. You will need about 6ft of ailine tubing, some tape (preferrable, but not required), a bucket that is used only for aquarium stuff, and a piece of wood (can be substituted).
You start with your bag of fish. Cut the top off and pour out a little bit of the water. Take the fish and pour them gently into the bucket (you will need to tilt the bucket and then place the block of wood underneath to prop it up.
Place it in front of the tank the fish are going to.
Take the airline tubing and tie 3 overhand knots into it and pull them a little tight, but not too tight. Stick one end of the hose into the tank and the other end into the bucket. Tape down both ends. Suck on the bottom end of the hose to start a siphon (use your own method if you don't want to put your mouth on the hose). Once the water starts flowing, tighten the knots you made previously until you get about 1 drop per second into the bucket. You may need to really tighten them down and can even include a 4th knot if needed.
Once you have flow established and everything is secure, cover the bucket to keep out most of the light. After about 2hrs, net the fish out of the bucket (do not pour the water in your tank) and place into your tanke. I usually take a mental note the water level that was in the bucket before I started dripping water into it to give me an idea of how much has dripped from the tank. You want it to be mostly your water by time the 2hrs has gone by. Once you put in the tank, keep the lights out for minimum 1hr.
That is all that is needed. This is slightly a pain to accomplish, but once you see how you start losing less fish right after you buy them you'll want to do this every time.