To get Chao close is rather complicated, but it is one of the greatest feets of the game. Below, I will explain all you need to know about getting two Chao close. It is a very deep and intriguing proces, so if you don't feel like putting some time to get your Chao happier, than skip this section and do somethin' else.

Starting the Relationships

       The first part is not hard, nor easy. You will first have to get two Chao (duh) and put them next to each other. How? The friendship should start as babies. Let them both learn some instruments. When one plays an instrument, get the other and put in near the Chao, and if it learned an instrument, it will start to play. If it doesn't, it will just watch. Make sure they do this frequently; this is just a minor step in getting the relationship started.
        Make sure they have a TV or other toys in the Garden already. When one goes to turn on the TV, pick up the other and put it next to the other Chao that it's friends with. ?If it doesn't watch TV with the other Chao, they haven't spent enough time together. 

Adultery and Growth

       The second part is cruel and harsh. Obviously, one Chao will be older than the other. This means one Chao will evolve before the other. This is a very sad time, because the Chao that evolved won't like the Chao it was friends with until that Chao evolves. Until then, just seperate them. Now make the Chao that was friends with the other Chao into the same type (Hero, Dark, Neutral) and put them in the same Garden. Now, you should let them do the stuff they normally did and let them get used to it.

        Once they are close to each other again, it's time for them to mate. Buy a couple of Heart Fruit and have them mate. Two times. Now, do all the steps with the babies as you did with these Chao, they are brothers/sisters. Put them in the Garden with the mother and father. Have them mate and do all the stuff they like to do -- and never get rid of the kids.

Reincarnation/Death

       The harshest of the three steps, reincarnation/death will make the other Chao sad. Now, when one reincarnates, the other will feel lonely, but this is just a cycle. The Chao that reincarnates is going to remember it's friend -- but not it's kids. Now, put the egg into a different Garden, and wait for the other Chao to reincarnate. Hatch them both, and repeat the process of friendship.

The 2nd + 3rd Lives

       This is when stuff starts to get serious. Once in a while, your Chao will that were friends will start walking together. They will sleep together. This is the best sign you can get -- they are now best friends. Do this with them until they become Chaos Chao and they won't go anywhere without each other! It is  extremely cute, and now, you should feel very proud, you acquired a big feet that is cool. Do it with a lot of Chao.

Jealousy and Fighting

       Sometimes, Chao become friends with other Chao, and the Chao that was friends with the Chao that made a new friend will get jealous. Now, the jealousy becomes a HUGE problem in a relationship. Sometimes, the Chao that was friends with the Chao that made a new friend will fight the Chao's new friend. You must stop this by punishing them; even though it might be mean. Now, in order for the Chao not to fight again, you must seperate one of them from teh Chao that was friend's with both. It may be harsh -- but you have to, or things will get ugly.