Transistors usually have 3 or 4 different wires comin' out. If you connect these wires in the wrong way the transmitter won't work. It may even explode. The picture below shows how to prevent from such an event. You can find the numbers and letters back in the soldering schematic.
Coils also require extra attention.
You can buy the coils trough ferrite in the shop, but the other ones have to be made yourself. Use 1mm AgCu wire. The best way to make a coil is to bend it around a pencil or other cilindrical shaped object tight. The diameter of the object is always d-coil minus 1 mm. In this case 9mm.