Planting trees correctly can be difficult. Most people don't notice one thing - the size of the tree. If you understand this, it makes it much easier. For example, if you plant one tree, then another one right next to it, one of them WILL NOT grow. Here's a guide to make your tree planting experience much better:
 Fruit Tree
 Get a Fruit
First off, you need a fruit. These all come from trees that are already planted. Your local fruits are the ones that started off in your town, and foreign fruits are ones that did not(these can be retrieved by various means, such as mailing request letters out to other villagers or simply borrowing some to plant from a friends linked Town). You can plant either type, but to being planting, I usually work with a foreign fruit, as you can get more Bells out of it. The only foreign fruit that is never seen in a town to start is the Coconut.
 Get a Shovel
Such a tool is also necessary for this productive task. You can buy one at Tom Nook's Store for 500 Bells if you don't already have one, they can be found in stock usually every day(especially if you've upgraded to Nookington's. You could also get a Silver Shovel from Resetti in the city. Any version of this tool will do, so long as one is in your posession.
 Dig a Hole and place the Fruit
Digging a hole is as simple as it comes. Just have the shovel equipped and press A on any game. Now, to throw the fruit in, you go to the menu, click on the fruit, and select the "Bury" option. Your character will automatically throw the fruit in and stamp dirt on top of it.
E = Empty spot
T = Tree
B = Building
R = River
C = Cliff
Below is the way to grow a tree.
E E E
E T E
E E E
These example tree locations will not grow.
Cliff blocking tree growth:
E E C
E T C
E E C
Building blocking tree growth:
B E E
B T E
B E E
Another tree located too close:
T E E
E T E
E E E
Located too close to the river:
E E E
E T E
R E E
 Do you want another tree? (OPTIONAL)
If so, here's what you have to do: After planting the tree you just planted, dig a hole right next to it. If you want your town to be organized, dig two holes (going right or left). These are used as spaceholders in order to prevent lacking patterns. Now, dig a hole at the end of the one/two holes. This is the one you will use for the fruit. Throw the fruit in, and that tree will also sprout.
 What do I do with the tree?
Nothing. Just let it grow, simple as that. If it doesn't grow, this could be because of one important factor: location. Some trees don't grow if you place them too close to something. For example, a tree right next to a building or posted sign probably won't sprout, because they both are up in the sky and both take up room. Remember these tips and you'll be fine.
 Money Trees
 Get some Bells
First things first: You need at least 1,000 Bells or this won't work at all. A popular theory is that the amount of bells buried effect the chance of the money tree sprouting. For example, 1000 bells would only give it a 1% chance of sprouting, where as 89,000 Bells would give you an 89% chance of the money tree sprouting. However the most important thing to remember, is that a money tree still grows like any other tree. If its position is bad, it won't grow just like any other.
 Animal Crossing GC
In Animal Crossing on the Gamecube, in order to grow a money tree, you first need to find the glowing patch of soil within your town. Buried there will be 1000 bells. To grow a money tree, you must bury the amount of bells you wish to grow. 30,000 bells is the maximum you can plant, if the tree grows successfully, it will bare 3 x 30,000 bags of bells, equalling 90,000 bells.
Note: You don't need a golden shovel for this. Although whether using one increases the chance of the money tree growing is unknown. You can only grow the money tree by planting it in the glowing patch, meaning only one per day can be planted, and the glowing patch may not be in a position enabling it to grow, so choose your patches carefully in order to not waste your bells!
 Animal Crossing Wild World
There are no glowing patches in Animal Crossing Wild World, but using a Golden Shovel allows you to plant money trees where ever you like. Please note, buring money with a regular shovel will not work, it must be golden in order for the tree to sprout. You can obtain a golden shovel by burying a regular Shovel for 24 Hours. After you dig it up, you will have a Golden Shovel.
 Plant the Bells
If you remember how to plant the Fruit, this is basically the same thing, but with a few changes. First off, you have to get a bag of bells by clicking on your amount of Bells in the menu and getting the Bells into a bag. Now, click on that bag and bury it in the hole.
Remember to plant your money tree in a good place so it has the best chance of sprouting. Although the theory of "more bells better growth" is popular, its not certain, so think carefully before buring ALL your bells.