Step one: Find a room with no breakable objects. This is the single most important thing on this entire page.
Start off with just one object. What that object should be depends on how much patience you have, how determined you are to learn, and what sorts of objects you can get. If you are patient and determined and have access to a set of juggling clubs, I would actually reccomend starting off with those instead of with balls or bean bags, because clubs force you to have perfect technique. If you don't satisfy these conditions, that's fine. Balls or hackey sacks will work fine.
Throw the object back and forth from hand to hand, just above head height. There are a few things you want to look for:
1. The object's path should be shaped roughly like a sideways figure 8. IT SHOULD ALL HAPPEN ON A SINGLE PLANE. That is, you should not reach forward as you throw it. It should only go up and down, side to side, never forward and back.
2. The object's path should be as consistent as possible.
3. See step one.
4. If you are using clubs, the club should flip once with every throw. You need to be able to flip the club back and forth from and to hand so easily that you can do it with your eyes closed without even thinking about it. Once you reach the point where you automatically flip the club jst right each time, clubs become easier than balls.
Work on this for as long as you can without dying of boredom. The limit is about two minutes for most people.
Now, pick up a second object, with one in each hand. Throw the first object, just like you did when you were only using one object. When it gets to its highest point and starts to drop, scoop under with your other hand and throw the second object in the same way that you threw the first. The distance between where the first object is comming down and where the second is going up should be about the same as the width of your hand. After you let go of the second object, move your hand into position to catch the first. Then, it should be fairly easy to catch the second.
5. See step one
Do this again and again for a while. Look for the sme things you were looking for with one object. Now do the same thing, exept in reverse: throw with the other hand first. For a description of the ball's ideal path, see step one. And in case I haven't mentioned this enough, IT NEEDS TO STAY ON A SINGLE PLANE. You should be able to do it in front of a wall without scraping your knuckles. This is the hardest and most important part of learning to juggle.
Now, for the third object. You will have one more object than you have hands (at least, I hope you will). Do exactly what you did with two objects, except you have to do it twice in a row (start with just twice, anyway). As the first object hits its peak, scoop under and throw the second one. As the second hits its peak, scoop under and throw the third. After that, just stop, and don't try to keep going for now. Work on that for a while. If you can't do that, then try doing it without any catches. Just let them hit the ground. And, if you're wondering what to look for in the ball's path, see step one, or one of the other places on this page where I've said IT NEEDS TO ALL HAPPEN ON A SINGLE PLANE. Am I repeating that too much? No I'm not; it really is that important.
If you're wondering why it is so important for it all to happen on one plane, here' why: 1. Reaching forward while juggling leads to sprint juggling. This is when you have to run accross the room to avoid dropping anything. The easiest way to cure this is to juggle while standing on the edge of a cliff. However, standing in front of a wall also works.
2. If it's on one plane, it's much easier to control.
3. Everybody reaches forward when they're just starting out.
4. If you ever hope to go to higher numbers, it is even more important. Four is difficult reaching forward, and more than that is impossible.
5. If you do clubs without them staying on the same plane, it will hurt.
6. I'll stop now, 'cause I could go on forever.
When you can do two consecutive throws consistently, try doing it three times in a row instead of two. Then four. Then as many as you can. Remember to always try to kep everything on the same plane. You should be able to juggle in front of a wall, and your hands and the objects should always remain the same distance from the wall.
Once you've got this, odds are high that you will be addicted to juggling for the rest of your life. Many people never go past three objects. However, once you get above four, it becomes much much more addictive, and leads to utter insanity. Once you get to five, you will probably never stop going for one more (i'm currently working on nine). Just work on three for now.