Here are a few helpful tips........
HOME SWEET HOME 
One very important aspect of bringing guinea pigs into your home: location!
Think about where you are going to put your guinea pig's home. Back in the rarely-visited guest bedroom? In the lonely garage or basement? Don't do that to a guinea pig! Guinea pigs need human contact and a stimulating environment. You'll notice very quickly that your piggy will react to feeding times and general noises in the room. The best place to put your guinea pig's home is in a room that you frequent, but one that is not too loud. Daily contact is a must, and there is no such thing as too much cuddling. Guinea pigs crave interaction.
Make sure the cage is away from direct sunlight and direct sources of heat. Guinea pigs can get hot very quickly. Also avoid drafts from fans, old/loose windows and vents. Guinea pigs are very susceptible to colds, which can be deadly.
Guinea pigs have a similar "comfort zone" to humans. They fare well in warm, but not hot, climates. Generally, your normal home temperature range (usually 65-75 degrees F) suits guinea pigs quite nicely.
Guinea pigs tolerate cold better than hot temperatures. Since they cannot sweat to cool themselves down, guinea pigs will stretch out and become lethargic as the heat rises. Heat exhaustion and death are very real risks to guinea pigs, so provide a means for them to stay cool in hot temperatures. A popular method is freezing water in plastic bottles so that they can lay next to the bottles to cool off. Of course, remove all labels, since guinea pigs are notorious nibblers. Anything that you place in their cage should be safe to eat.
Note, however, that guinea pigs do not tolerate temperature fluctuations either, so controlling their environment is important.
GETTING TO KNOW YOU 
You can leave your new guinea pig alone for the first day so that he can become accustomed to the new sounds and smells around him. Guinea pigs are creatures of habit, and this sudden change of scenery is bound to stress them out. However, pick up and cuddle your new piggy often so he can get to know you — your smell, the sound of your voice, the warmth of your hands. Even though guinea pigs may never quite warm to the idea of being picked up (some of mine still run after three years!), they need to learn to trust you and develop a bond.