Buy some tools and use search engines like Yahoo! for the instructions.
While using mobiles, we often suffer from some problems and pay a huge amount to the repairmen. There are many problems regarding a mobile which can be solved by yourself by using some basic tools and information. You can buy a tool kit and search for the solutions at Yahoo! There are many websites which provide free tutorials for repairing mobiles along with the circuit diagrams.
For example, if you dropped your mobile and its switches are not working. You can open it using a screw driver and follow the instructions after thoroughly studying the diagram to replace the damaged switches. If you have little knowledge about circuits you can easily deal with all kind of physical problems.